Ice-making device

ABSTRACT

A compact ice-making device is provided for making ice chips of varied shapes for use in glasses of whiskey and water, and the like purposes. Ice is made using an ice-making vessel ( 13 ) for making a plank-like block of ice with a shaft ( 18 ) inserted in advance in the vessel, the shaft ( 18 ) having ribs ( 18 A) extending substantially radially from a rotating axis. Upon completion of the ice making, a gear unit ( 20 ) connected to the shaft ( 18 ) is driven by a motor to rotate the shaft ( 18 ), which cracks and divides the plank-like ice block into ice chips of varied shapes.

This application is a U.S. national phase application of PCTInternational Application PCT/JP2004/003065.

TECHNICAL FIELD

The present invention relates to an ice-making device capable of makingice chips of varied shapes.

BACKGROUND ART

In household refrigerators and the like, there has hitherto been a wideuse of automatic ice-making device (hereinafter referred to asice-making device) for storing and freezing water supplied from awater-supply pipe into an ice-making vessel, and releasing the producedice cubes by means of a drive unit which turns the ice-making vesselupside down.

Description is provided hereinafter of one such ice-making device of theprior art with reference to the accompanying drawings. FIG. 26 shows anoverall structure of the ice-making device in the conventionalrefrigerator.

FIG. 27 is a structural illustration of an ice-making unit of theconventional ice-making device. As shown in FIG. 26 and FIG. 27, maincabinet 75 of the refrigerator comprises outer cabinet 76, inner cabinet77, and insulating material 78 filled in a space between outer cabinet76 and inner cabinet 77. Compartment wall 79 separates the interior ofthe refrigerator's main cabinet 75 into upper and lower spaces. Theupper space forms freezer compartment 70 and the lower space formsrefrigeration compartment 71. Blower 73 forcefully delivers cold airchilled by evaporator 72 in a refrigeration cycle provided on the backwall of freezer compartment 70 in a manner to circulate through freezercompartment 70 and refrigerator compartment 71.

Ice-making device 74 disposed inside freezer compartment 70 comprisesdrive unit 85 having built-in motor (not shown in the figure), reductiongear (not shown) and the like, ice-making vessel 87 having support shaft86 connected to its center part, frame 88 for turnably supportingice-making vessel 87 to drive unit 85, and so on.

Frame 88 is provided with stopper 89 at one part of it to deform theshape of ice-making vessel 87 in order to release ice cubes. Inaddition, ice-making vessel 87 has flange 90 in a position to strikeagainst stopper 89.

There is ice storage box 81 disposed underneath ice-making device 74.Water tank 82 for storing supply of water for ice making is removablyplaced in one section of refrigerator compartment 71. Water tank 82 hasvalve 84 to open and close water supply port 83.

Water reservoir 95 is located under water supply port 83 of water tank82. When water tank 82 is placed with water supply port 83 downward,valve 84 is pushed up to open water supply port 83. Water pump 96 pumpsup the water received in water reservoir 95. Water-supply pipe 97connected to water pump 96 is disposed to open its outlet in ice-makingvessel 87 of ice-making device 74.

This conventional ice-making device 74 operates in a manner as describedhereinafter. When the user fills water tank 82 with water and places itin a given position, valve 84 is pushed up to open water supply port 83and deliver the water to fill water reservoir 95. The delivered water isthen pumped up by water pump 96, and supplied into ice-making vessel 87through water pipe 97. The water of a predetermined amount thus suppliedin ice-making vessel 87 is frozen by the refrigerating function insidefreezer compartment 70 to form ice cubes.

Upon completion of ice making, a turning motion of drive unit 85 causesice-making vessel 87 to turn upside down around support shaft 86 untilflange 90 strikes upon stopper 89. Ice-making vessel 87 is therebytwisted and deformed to release the ice cubes into ice-making vessel 87.The released ice cubes fall in storage box 81 and they are storedtherein. After the ice cubes are released, ice-making vessel 87 isreturned again to the original position by a reversed turning motion ofdrive unit 85.

The automatic ice making and storage is continued thereafter byrepeating the above operation until the water in water tank 82 is usedup completely.

On the other hand, there are a number of methods that determine shapesof produced ice cubes, one of which is to use an ice-making vessel ofcertain shape as described in the above example of the prior art, andanother one is to make a comparatively large block of plank-shaped iceand to crack it into pieces. An example of the latter method isdisclosed in Japanese Patent Unexamined Publication, No. H08-86548.

Description is provided hereinafter of the above ice-cracking device ofthe prior art, by referring to the accompanying drawings.

FIG. 28 is a partially sectioned side view of such conventionalice-cracking device, and FIG. 29 is a longitudinally-sectioned side viewof the same conventional ice-cracking device. Box-shaped frame 148 has arecessed portion 149 in the top plate, where feed opening 150 is formedfor feeding a block of ice “H”. Cover 150A closes feed opening 150. Theinterior of frame 148 is divided into upper and lower sections bybulkhead 152 having discharge opening 151 for discharging cracked piecesof ice “K”. Container 153 for storing the cracked ice “K” is securedbelow discharge opening 151.

At one side of container 153 facing front opening 154, U-shaped stopper156 is held to container 153 with pin 157 in a freely rotatable mannerso that it normally stays in abutment against the back of door 155attached to frame 148, and follows the opening and closing motions ofdoor 155. Ice-cracking unit case 159 formed integrally with hopper 158is secured above discharge opening 151, and hopper 158 is capable oftaking a block of ice “H” having a mass of about 4 kg generally used forcommercial purpose.

Upper opening 160 of hopper 158 is arranged in communication to feedopening 150.

Ice-cracking unit case 159 is provided therein with two rotors 161 and162 mounted to shafts 163 and 164 with a predetermined distance in afreely rotatable manner, as shown in FIG. 29. Both of rotors 161 and 162are provided with two or three arms 165 and 166 in a protruding mannerat regular intervals along the axial direction thereof according tocracking sizes of ice, and first smashing pins 167 and 168 are mountedto these arms 165 and 166 respectively. Rotors 161 and 162 are alsoprovided with two or three arms 169 and 170 at regular intervals in thesame protruding manner along the axial direction, but at an angle of 180degrees from first smashing pins 167 and 168. Arms 169 and 170 also havesecond smashing pins 171 and 172 mounted respectively thereto. There isprovided a ridge-shaped pedestal for supporting the block of ice “H” tobe cracked by first smashing pins 167 and 168 and second smashing pins171 and 172 one after another.

The pedestal has a number of arc-shaped grooves 174 formed in areaswhere the tips of the smashing pins are allowed to travel through.

Ends of shafts 163 and 164 at one side of both rotors 161 and 162 areextended outside of ice-cracking unit case 159, and connected with theirrespective timing gears 175 and 176 in a manner that first smashing pin167 of rotor 161 is shifted at a 90-degree angle from another firstsmashing pin 168 of rotor 162, as shown in FIG. 28. Shaft 164 of rotor162 is also connected with sprocket wheel 177 which is then engaged bychain 179 to another sprocket wheel 178 fixed to a main shaft of motor Mmounted to the exterior sidewall of hopper 158.

In ice-cracking device constructed as above, when a block of ice “H” isthrown in hopper 158, rotors 161 and 162 rotate, and first and secondsmashing pins 167, 168, 171 and 172 on rotors 161 and 162 alternatelystrike the block of ice “H” to crack it gradually from its leading end.

In the above structure of the conventional ice-making device, however,cubes of ice it produces have same shape at all times since aconfiguration of the ice-making vessel determines the shape of icecubes. In addition, the ice cubes need to be so shaped that side facesare sloped and edges are rounded in order to release the ice cubes fromthe ice-making vessel by twisting it at the end of ice making. It is forthis reason that the device could provide only ice cubes of undesirableshape in appearance for use in beverages such as whiskey and water.

On the other hand, the ice-making device may be equipped with anice-cracking device to provide ice cubes of desirable shape inappearance, but this requires a conveyer unit for transferring blocks ofice from an ice-making unit through the hopper to the rotors in orderfor the conventional ice-cracking device to break the ice into pieces.

There was also a drawback that the ice-making device becomes quite bulkyin size since the rotors must have dimensions enough to hold a block ofplank-shaped ice, and the ice-making unit and the conveyer unit needrespectively large capacities to carry the block of ice. Furthermore, itrequires a comparatively large motor in order to deliver a large torquesufficient to break the block of ice, and this was also the factor ofmaking the ice-making device so large.

The present invention addresses the above problems of the prior art, andto provide an ice-making device of small size, yet capable of makingirregularly-shaped chips of ice not having excessively sloped side facesand rounded edges, which are desirable in appearance for use in suchbeverages as whiskey and water,

SUMMARY OF THE INVENTION

An ice-making device of the present invention comprises an ice-makingunit for making a plank-shaped block of ice, cracking means for crackingthe plank-shaped block of ice produced in the ice-making unit into aplurality of ice chips within the ice-making unit, a drive unit fordriving the cracking means, and a water supply unit for supplying waterto the ice-making unit. The device can thus crack the plank-shaped blockof ice to make sharp-cut chips of ice rather than round-edge cubes.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional side view of a refrigerator equipped with anice-making device according to a first exemplary embodiment of thepresent invention.

FIG. 2 is a perspective view of the ice-making device according to thefirst exemplary embodiment of this invention.

FIG. 3 is an exploded view of the ice-making device according to thefirst exemplary embodiment of this invention.

FIG. 4 is a top view of the ice-making device according to the firstexemplary embodiment of this invention.

FIG. 5 is a perspective view of an ice-making unit and an ice-crackingunit of an ice-making device according to a second exemplary embodimentof this invention.

FIG. 6 is a top view of the ice-making device according to the secondexemplary embodiment of this invention.

FIG. 7 is a sectional view taken along the line A-A of the ice-makingdevice according to the second exemplary embodiment of this invention.

FIG. 8 is a perspective view of a part of ice-making device according toa third exemplary embodiment of this invention.

FIG. 9 is an exploded view of the ice-making device according to thethird exemplary embodiment of this invention.

FIG. 10 is a flow chart showing a main part of control operationperformed by a control unit according to the third exemplary embodimentof this invention.

FIG. 11 is a flow chart showing a main part of control operationperformed by an ice-making device according to a fourth exemplaryembodiment of this invention.

FIG. 12 is a flow chart showing a main part of control operationperformed by an ice-making device according to a fifth exemplaryembodiment of this invention.

FIG. 13 is a flow chart showing a main part of control operationperformed by an ice-making device according to a sixth exemplaryembodiment of this invention.

FIG. 14 is a perspective view of an ice-making device according to aseventh exemplary embodiment of this invention.

FIG. 15 is a sectional view of a main part of the ice-making deviceshowing an ice-cracking operation according to the seventh exemplaryembodiment of this invention.

FIG. 16 is a perspective view of an ice-making device according to aneighth exemplary embodiment of this invention.

FIG. 17 is an exploded perspective view of the ice-making deviceaccording to the eighth exemplary embodiment of this invention.

FIG. 18 is a sectional view of a main part of the ice-making deviceaccording to the eighth exemplary embodiment of this invention.

FIG. 19 is a sectional view of another main part of the ice-makingdevice according to the eighth exemplary embodiment of this invention.

FIG. 20 is a sectional view of still another main part of the ice-makingdevice according to the eighth exemplary embodiment of this invention.

FIG. 21 is a graphic representation showing a relation between swingangle and clarity of ice in the ice-making device according to theeighth exemplary embodiment of this invention.

FIG. 22 is a graphic representation showing a relation between swingfrequency and clarity of ice in the ice-making device according to theeighth exemplary embodiment of this invention.

FIG. 23 is a perspective view of an ice-making device according to aneleventh exemplary embodiment of this invention.

FIG. 24 is an exploded perspective view the ice-making device accordingto the eleventh exemplary embodiment of this invention.

FIG. 25 is an exploded perspective view of an ice-making deviceaccording to a twelfth exemplary embodiment by this invention.

FIG. 26 is an overall structure of an ice-making device in aconventional refrigerator.

FIG. 27 is a structural illustration of an ice-making unit of theconventional ice-making device.

FIG. 28 is a partially sectioned side view of a conventionalice-cracking device.

FIG. 29 is a longitudinally sectioned side view of the conventionalice-cracking device.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to the accompanying drawings, description will be providedhereinafter of certain examples of the preferred embodiments accordingto the present invention. Like reference numerals will be usedthroughout to designate like components as those of the prior artstructures, and details of them will be skipped. The preferredembodiments described herein should be considered as illustrative, andtherefore not restrictive of the scope of this invention. Arefrigeration promoting member used in this invention is cooled directlyby chilled air in a range of freezing temperatures for the purpose ofexpediting cooling of a cooling plate, and it is composed of a materialhaving good thermal conductivity such as aluminum. This refrigerationpromoting member may be additionally provided with a plurality offin-like vanes on its plate base. The structure of such configurationcan increase a surface area exposed to the chilled air, therebyimproving a cooling effect of the refrigeration promoting member.

First Exemplary Embodiment

Referring now to FIG. 1 through FIG. 4, description is provided of thefirst exemplary embodiment.

Refrigerator/freezer's main cabinet 1 (hereinafter referred to as maincabinet 1) has a plurality of storage compartments, of which firstrefrigerator compartment 2 formed in the upper part of it is enclosedand thermally insulated from the external air by door 3 and insulationwall 4. Freezer compartment 5 (hereinafter referred to as ice-makingcompartment 5) formed under first refrigerator compartment 2 is enclosedand thermally insulated from the external air by insulation wall 4 anddoor 6. Ice storage box 5A for storing ice cubes is disposed to thelower space of ice-making compartment 5. Second refrigerator compartment7 located between first refrigerator compartment 2 and ice-makingcompartment 5 is enclosed and thermally insulated from the external airby insulation wall 4 and door 8. First refrigerator compartment 2 andsecond refrigerator compartment 7 are connected through an air path forpassage of chilled air.

Ice-making device 100 comprises water supply unit 200, ice-making unit300, and ice-cracking unit 400. Water supply unit 200 comprises watertank 10 placed in first refrigerator compartment 2, water pump 11, andwater supply path 12 disposed in a manner to penetrate from firstrefrigerator compartment 2 to ice-making compartment 5 throughinsulation wall 4. Ice-making unit 300 comprises ice-making vessel 13having an open top and open bottom for temporarily storing water andmaking a plank-shaped hexahedral block of ice, cooling plate 16 fixed toice-making vessel 13 in a manner that one side surface comes into closecontact to and composes a bottom wall of ice-making vessel 13 and theother side surface is in close contact to one surface of Peltier device14 via heat conduction member 15, and heat sink 17 bonded to the othersurface of Peltier device 14.

In addition, cooling plate 16 is provided with two cylindrical posts 16Ahaving openings in both top and bottom and a height generally equal tothat of ice-making vessel 13. These cylindrical posts 16A are mountedperpendicularly to cooling plate 16 toward the open top side ofice-making vessel 13 in such positions that divide a longitudinal lengthof ice-making vessel 13 into three generally equal parts along a linenear the center of the short sides. Ice-cracking unit 400 used as acracking means comprises two shafts 18, each having an outer shellcovering each of cylindrical posts 16A mounted to cooling plate 16 and adriving axle penetrating cooling plate 16 through a hole in cylindricalpost 16A, and gear unit 20 provided with driving shafts 19 connected tothe respective driving axles of two shafts 18.

Each of shafts 18 has four ribs 18A protruding in a radial direction ofthe rotating axis from the outer shell at generally 90-degree angleswith respect to one another to such an extent that they do not interferewith other ribs 18A of adjacent shaft 18 or come in contact to the sidewalls of ice-making vessel 13. Gear unit 20 reduces a speed of motor 21by a plurality of reduction gears 22 and the like, and rotates drivingshafts 19 simultaneously in the same direction. Gear unit 20 is fixed toice-making unit 300 in a position between cooling plate 16 and heat sink17 in a manner to become integral with ice-making unit 300.

In addition, ice-making unit 300 and ice-cracking unit 400 are disposedin a rotatable manner by means of driving mechanism 23 and driving shaft24, which are for turning ice-making unit 300 and ice-cracking unit 400.Ice-making vessel 13 is placed under a discharge port of water supplypath 12 at the upper space inside ice-making compartment 5. Ice-makingvessel 13 is thus located above ice storage box 5A in a manner that aperiphery of it is buried partly in insulation wall 4 between ice-makingcompartment 5 and the second refrigerator compartment 7.

Ice-making device 100 constructed as above operates in a manner which isdescribed next. Water pump 11 is driven only for a predetermined numberof times of a given duration at predetermined intervals tointermittently supply only a predetermined amount of water in water tank10 to ice-making vessel 13 through water supply path 12.

Cooling plate 16 located in the bottom surface of ice-making vessel 13is cooled by Peltier device 14 through heat conduction member 15, andconverts water inside ice-making vessel 13 from the liquid phase tosolid phase, when Peltier device 14 is supplied with a DC current of apredetermined direction. Heat from Peltier device 14 is dissipated bythe chilled air in ice-making compartment 5 during this period since aheat-generating surface of Peltier device 14 is fixed to heat sink 17.

According to this structure, a temperature of cooling plate 16 can beregulated by controlling the current supplied to Peltier device 14,which can hence control a freezing speed.

In this exemplary embodiment, a driving time of water pump 11 is soadjusted that it supplies the water of an amount that rises 0.5 mm inwater level in ice-making vessel 13 at each operation for a total numberof 40 operations. A temperature surrounding ice-making vessel 13 isinfluenced by the temperature of second refrigerator compartment 7, andit is usually higher when compared to that of a space around ice storagebox 5A located under the ice-making unit which is maintained in therange of freezing temperatures. However, the temperature surroundingice-making vessel 13 is regulated to approximately 0 deg-C., whennecessary, with a heater (not shown) disposed inside insulation wall 4above ice-making vessel 13 between second refrigerator compartment 7 andice-making compartment 5. This can help the ice to develop only from thebottom surface. In addition, an amount of the current supplied toPeltier device 14 is so adjusted as to maintain cooling plate 16 to sucha temperature that makes the freezing speed constant to bring thesupplied water into frozen in a two-hour duration.

Moreover, the driving time intervals of water pump 11 are so adjustedthat it starts supplying subsequent amount of water before water of theprevious supply becomes completely frozen. In addition, drivingmechanism 23 repeats an operating cycle in which ice-making unit 300 andice-cracking unit 400 are turned and tilted to a predetermined angle,kept still in the tilted position for a given time, and tilt them againto the opposite direction. In the instance of this exemplary embodiment,ice-making vessel 13 is tilted to a 15-degree angle in one direction,and it is kept in this tilted position for 5 seconds before being tiltedto the other direction, and this cycle is repeated until the ice makingis completed.

Completion of the ice making is determined when a temperature detectedby a temperature sensor (not shown) mounted to ice-making vessel 13becomes lower than a predetermined temperature after an elapse of apredetermined time following the given operating cycles of water pump11.

Upon completion of the ice making, a current of the reverse direction issupplied to Peltier device 14 for a predetermined duration to remove theice off the bottom of cooling plate 16. Following the above, motor 21 ongear unit 20 of the ice-cracking unit is energized for a predeterminedtime period to rotate two shafts 18 simultaneously only to a certainangle by way of reduction gears 22, driving shaft and the like. Therotation of shafts 18 imposes a turning force to the ice block while theice block is restricted from making such turning movement by the sidewalls of ice-making vessel 13. This results in concentration of stressesgiven in the ice by ribs 18A of shafts 18, which in turn producesoutward cracks in the ice from around shafts 18, and cracks theplank-shaped block of ice into a plurality of irregularly-shaped chipswithout round edges.

When the ice is completely cracked, driving mechanism 23 turnsice-making unit 300 and ice-cracking unit 400 upside down, and the chipsof ice fall as they are into ice storage box 5A because they areseparated from ice-making vessel 13 when cracked into pieces.

In ice-making device 100 of this exemplary embodiment, as describedabove, the water is supplied intermittently to maintain a thin layer ofunfrozen state of water at all the time, while the water is graduallyfrozen upward from the bottom of ice-making vessel 13 of ice-making unit300. This helps the air dissolved in the water to form air bubbles anddiffuse into the surrounding air, and thereby this device can produceice of high clarity.

In addition, this device repeats the motion of tilting and stoppingice-making vessel 13 while making ice, which moves a boundary surfacebetween the ice and water, separates air bubbles formed on the boundarysurface by the flow of water, and facilitates the air bubbles to diffuseinto the air around ice-making vessel 13 by their own buoyancy.Accordingly, this device can produce the highly clear ice in acomparatively fast speed.

In ice-cracking unit 400 used as cracking means of the plank-shaped ice,a torque required for shafts 18 to crack the ice differs depending onthickness and shape of the ice. The torque necessary for each of theshafts is approximately 2 to 6 Nm in the case of ice having a thicknessof about 20 mm used in this exemplary embodiment. In other words, it isa torque that can be obtained easily with any ordinary DC motor, so asto realize a compact ice-cracking unit of small size at low cost. Thisice-making device can thus provide highly clear ice chips of variedshapes with no rounded edge, and sensually excellent for use inbeverages such as whiskey and water. The cracks are likely to develop inthe directions of rotation of the tips of ribs 18A as well as thedirections extending linearly along the line between two axes ofrotation of shafts 18. It is therefore feasible to control how cracksare made in the ice to some extent. It is also possible to reduce anamount of finely crushed ice fragments by arranging the protrudingdirection of one of four ribs 18A on one shaft 18 in alignment linearlywith another one of four ribs 18A on the adjoining shaft 18.

As illustrated in this exemplary embodiment, simultaneous rotation oftwo shafts 18 having four ribs 18A can crack the block of ice intogenerally six pieces.

Numbers of shafts 18 or ribs 18A may be increased if desired to increasethe number of cracked pieces from the plank-shaped block of ice.

On the other hand, the plurality of shafts 18 needs not be rotate at thesame time to crack the ice. However, it is desirable to rotate theplurality of shafts 18 simultaneously in order crack the ice properlywith the simple structure of this ice-making unit, since the ice shouldbe secured to avoid rotation with any of shafts 18.

The block of ice can be cracked by rotating shafts 18 even when thebottom of ice block remains stuck on the cooling plate. However, it ismore desirable to rotate shafts 18 after loosening the ice block fromthe cooling plate, because it is more likely to produce finely crushedice fragments if the cracking motion is initiated before loosening theice from the cooling plate.

It is also feasible to crack the block of ice by heating shafts 18 andpiercing them into the ice block gradually while melting the ice onlyafter the ice block is completed, and shafts 18 rotated after the iceblock is refrozen again. However, this operation requires two motions ofshafts 18, a vertical motion and a rotary motion, which makes morecomplex the structure of gear unit 20 for driving shafts 18. Althoughthis structure can still achieve ice-cracking unit 400 of a size smallerthan the conventional ice-cracking unit, it is desirable to set shafts18 inside the space of ice block in advance in order to further reducethe overall size of ice-making device 100.

In this exemplary embodiment, hollow cylindrical posts 16A are mountedperpendicularly upward from the bottom surface of ice-making unit 300 tothe height generally equal to that of ice-making vessel 13, and shafts18 are inserted to cover them in order that the open top ends of posts16A are kept not lower than a surface of the water supplied intoice-making vessel 13.

As a result, this structure can improve reliability of preventingleakage of water (i.e., sealing) since shafts 18 are not inserteddirectly through the bottom surface of ice-making vessel 13 where wateris supplied.

The structure also facilitate removal and replacement of shafts 18 ofdifferent rib configuration as well as any other parts, when necessaryto adjust them according to different thickness of ice blocks or shapesof cracked ice chips, since shafts 18 are simply inserted to covercylindrical posts 16A.

In this exemplary embodiment, however, cylindrical posts 16A are notnecessarily used as stated above. Instead, shafts 18 may be inserteddirectly through the bottom surface of ice-making vessel 13 if asuitable design is taken into account for the sealing structure aroundinsertion holes in the bottom surface of ice-making vessel 13. When sucha structure is adopted, the height of shafts 18 protruding in ice-makingvessel 13 needs not necessarily be higher than the water surface, butshafts 18 can be inserted to any depth to yield the optimum effect ofice cracking.

Because the shafts in this exemplary embodiment are designed to have theheight enough to protrude above the upper surface of ice block, theice-cracking force of the shafts is imparted to the entire area from thebottom surface to the upper surface of ice block, thereby making it easyto control how the ice block is cracked.

In this exemplary embodiment, although ice-making device 100 wasillustrated as being mounted to the interior of main cabinet 1, it isnot intended to limit the scope of this invention to the abovestructure. Ice-making device 100 may be provided on itself with acooling device for cooling the exterior area thereof for use as a smallice-making device.

Second Exemplary Embodiment

Description is provided of an ice-making device of the second exemplaryembodiment with reference to FIG. 5 through FIG. 7.

Like reference numerals are used to designate like components as thoseof the first exemplary embodiment, and details of them will be skipped.

Ice-making device 100 comprises water supply unit 200, ice-making unit501, and ice-cracking unit 502 for use as ice-cracking means

Ice-making unit 501 comprises ice-making vessel 503 having an open topand open bottom with side surfaces sloped in a direction to make the topopening larger in area than an area of the bottom opening, fortemporarily storing water and making a plank-shaped block of ice,cooling plate 504 fixed to ice-making vessel 503 in a manner that oneside surface comes into close contact to and composes a bottom wall ofice-making vessel 503 and the other side surface is in close contact toone surface of Peltier device 14 via heat conduction member 15, and heatsink 17 bonded to the other surface of Peltier device 14. Ice-crackingunit 502 comprises two shafts 505 inserted through two holes bored incooling plate 504, and gear unit 506 provided with driving shafts 19connected to their respective shafts 505. There are sealing members 507formed of nitrile rubber or the like material attached from the sidefacing gear unit 506 to the inserting spaces of cooling plate 504 andshafts 505, and sealing members 507 are coated with grease on theirsurfaces in contact with shafts 505. As a result, there is hardly anychance of water in the ice-making unit to leak into the space of gearunit 506.

An upper portion of each shaft 505 extending above cooling plate 504 hasfour ribs 505A formed in a manner to protrude in a radial direction ofthe rotating axis of shaft 505 at generally 90-degree angles withrespect to one another to such an extent that they do not interfere withother ribs 505A of adjacent shaft 505 or come in contact to the sidewalls of ice-making vessel 503, and that protruding length of ribs 505Ais longer at the lower side of shaft 505 near cooling plate 504 than theupper end facing the top opening of ice-making vessel 503. Shafts 505 isformed to have a height smaller than the height of ice block made insideice-making vessel 503.

Gear unit 506 reduces a speed of motor 21 by a plurality of reductiongears 506A and the like, and rotates driving shafts 19 simultaneously indifferent directions to each other.

Two shafts 505 are so disposed that one of four ribs 505A is generallyin alignment linearly with one of four ribs 505A of the adjoining shaft505, as well as a line drawn in phantom between the end of the rib atthe side of the rotating direction and the center of rotation.

Ice-making unit 501 and ice-cracking unit 502 are fixed integrally in arotatable manner with driving mechanism 23 and driving shaft 24.

Description is provided hereinafter of an operation after theice-making, in ice-making device 100 serving as the main deviceconstructed as above according to the present invention.

Upon completion of the ice making, gear unit 506 is driven to turn twoshafts 505 at the same time, which breaks a plank-shaped block of iceformed in ice-making vessel 503, and the broken ice chips fall into theice storage box when ice-making unit 501 is reversed together withice-cracking unit 502 by driving mechanism 23.

In ice-making device 100 of this exemplary embodiment, a turning forceis imposed on the ice when shafts 18 are driven, as stated above.However, such turning movement of the ice is restricted due to rotatingdirections of the two shafts which are opposite to each other, andconcentration of stresses imparted to the ice block around the ends ofribs 505A causes the ice to crack apart.

Once the ice block is cracked, the cracked pieces of ice are freelymovable along the side walls of ice-making vessel 503 even if shafts 505rotate continuously because the side walls of ice-making vessel 503 aresloped. Therefore, gear unit 506 does not require a large torque todrive shafts 505 after the ice block is cracked.

This structure produces different patterns of cracks in the ice blockalong the vertical direction of ice-making vessel 503, because ribs 505Aare so formed that the protruding length is longer at the side nearcooling plate 504 than the upper end facing the top opening ofice-making vessel 503. That is, this configuration can crack the iceblock into more irregular shapes.

If ice block is made with shafts 505 designed to extend beyond the watersurface, the ice is frozen with convexed surface in the vicinities ofshafts 505 as compared to the other areas due to the surface tension ofwater. When shafts 505 are rotated to crack the ice block under suchcondition, parts of the ice around the convexed areas get stuck onshafts 505, and they occasionally remain stuck even after the ice-makingunit is turned upside down to discharge the cracked ice. Measures needto be taken in this case in order to positively release the ice pieces,such that shafts 505, are rotated for several times after the ice blockis cracked to loosen and disengage the stuck pieces. In the structure ofthis exemplary embodiment, on the other hand, the height of shafts 505is so fixed that it is smaller than the height of the ice block formedinside ice-making vessel 503, so as to make the ice having a nearly flatsurface in the end. Accordingly, this structure ensures complete releaseof the cracked ice pieces since no ice gets stuck on shafts 505 todisturb falling pieces of the cracked ice.

When the function of the shafts can be met with a small angle ofrotation, the gears serving for the driving shafts in the gear unit needto be formed of only certain angles instead of forming the entire360-degree angle, and this can further reduce the size of the gear unit.

The shafts may be made of a metallic material having a high resistanceto corrosion with sufficient strength such as stainless steel in orderto prolong a useful life of the ice-cracking unit, and to make it freefrom maintenance.

Alternatively, the shafts may be made of a plastic material having ahigh rigidness such as polyacetal, which can reduce the cost of theshafts because of the excellent mouldability.

Third Exemplary Embodiment

Description is provided of ice-making device 100 of the third exemplaryembodiment with reference to FIG. 1 and FIG. 8 through FIG. 10. Likereference numerals are used to designate like components as those of thefirst exemplary embodiment, and details of them will be skipped.

Refrigerator/freezer's main cabinet 1 (hereinafter referred to as maincabinet 1) has a plurality of storage compartments, and firstrefrigerator compartment 2 formed in the upper part of it is enclosedand thermally insulated from the external air by door 3 and insulationwall 4. Freezer compartment 5 (hereinafter referred to as ice-makingcompartment 5) formed under first refrigerator compartment 2 is enclosedand thermally insulated from the external air by insulation wall 4 anddoor 6. Ice storage box 5A for storing ice chips is disposed to thelower space of ice-making compartment 5. Second refrigerator compartment7 located between first refrigerator compartment 2 and ice-makingcompartment 5 is enclosed and thermally insulated from the external airby insulation wall 4 and door 8. First refrigerator compartment 2 andsecond refrigerator compartment 7 are connected through an air path forpassage of chilled air.

Ice-making device 100 comprises water supply unit 200, ice-making unit300, and ice-cracking unit 400. Water supply unit 200 comprises watertank 10 placed in first refrigerator compartment 2, water pump 11, andwater supply path 12 disposed in a manner to penetrate from firstrefrigerator compartment 2 to ice-making compartment 5 throughinsulation wall 4. Ice-making unit 300 comprises ice-making vessel 43having an open top and open bottom for temporarily storing water andmaking a plank-shaped hexahedral block of ice, cooling plate 46 fixed toice-making vessel 43 in a manner that one side surface comes into closecontact to and composes a bottom wall of ice-making vessel 43 and theother side surface is in close contact to one surface of Peltier device14 via heat conduction member 45, and heat sink 47 bonded to the othersurface of Peltier device 14.

In addition, cooling plate 46 is provided with two cylindrical posts 46Ahaving openings in both top and bottom and a height generally equal tothat of ice-making vessel 43. These cylindrical posts 46A are mountedperpendicularly to cooling plate 46 toward the open top side ofice-making vessel 43 in such positions that divide a longitudinal lengthof ice-making vessel 43 into three generally equal parts along a linenear the center of the short sides. Ice-cracking unit 400 comprises twoshafts 48, each having an outer shell covering each of cylindrical posts46A mounted to cooling plate 46 and a driving axle penetrating coolingplate 46 through a hole in cylindrical post 46A, and drive unit 50(hereinafter referred to as gear unit) provided with driving shafts 49connected to the respective driving axles of two shafts 48. Shafts 48function as cracking means which are rotatory driven inside ice-makingunit 300 for cracking a plank-shaped block of ice into chips. Each ofshafts 48 has four ribs 48A protruding in a radial direction of therotating axis from the outer shell at generally 90-degree angles withrespect to one another to such an extent that they do not interfere withother ribs 48A of the adjacent shaft 48 or come in contact to the sidewalls of ice-making vessel 43. Gear unit 50 reduces a speed of motor 51by a plurality of reduction gears 52 and the like, and rotates drivingshafts 49 simultaneously in the same direction. Gear unit 50 is fixed toice-making unit 300 in a position between cooling plate 46 and heat sink47 in a manner to become integral with ice-making unit 300.

In addition, ice-making unit 300 and ice-cracking unit 400 are disposedin a rotatable manner by means of driving mechanism 53 and driving shaft54, which are for turning ice-making unit 300 and ice-cracking unit 400.Ice-making vessel 43 is placed under a discharge port of water supplypath 12 at the upper space inside ice-making compartment 5. Ice-makingvessel 43 is thus located above ice storage box 5A in a manner that aperiphery of it is buried partly in insulation wall 4 between ice-makingcompartment 5 and the second refrigerator compartment 7.

Temperature sensor 55 is disposed in the vicinity of ice-making vessel43 on cooling plate 46 for detecting a state of water inside ice-makingvessel 43. Temperature sensor 55 is thermally insulated except for asurface that is in contact with cooling plate 46. A thermistor is oneexample of such components used for temperature sensor 55.

Ice-making device 100 is controlled by a control unit (not shown).

Ice-making device 100 constructed as above operates in a manner which isdescribed next.

FIG. 10 is a flow chart showing a main part among a number of controloperations of ice-making device 100 performed by the control unitaccording to this invention. When an ice-making control begins andtemperature sensor 55 detects a temperature below a predetermined value(STEP 1), driving mechanism 53 starts swinging operation for repeating acycle consisting of turning ice-making unit 300 and ice-cracking unit400 to a predetermined degree of tilting angle, holding them at thetilted angle for a predetermined time, and turning them in the oppositedirection (STEP 2). In this exemplary embodiment, ice-making vessel 43is tilted to 15 degrees in one direction, and again tilted to 15 degreesin the opposite direction after holding it at the tilted position for 5seconds, and this cycle is repeated until the ice-making process ends.

Water pump 11 is driven only for a predetermined number of times of agiven duration at predetermined intervals to intermittently supply onlya predetermined amount of water in water tank 10 to ice-making vessel 43through water supply path 12 (STEP 3).

Cooling plate 46 located in the bottom surface of ice-making vessel 43is cooled by Peltier device 14 through heat conduction member 45, andconverts water inside ice-making vessel 43 from the liquid phase tosolid phase, when Peltier device 14 is supplied with a DC current of apredetermined direction (hereinafter referred to as a positive current).Heat from Peltier device 14 is dissipated by the chilled air inice-making compartment 5 during this period since a heat-generatingsurface of Peltier device 14 is fixed to heat sink 47. According to thisstructure, a cooling capacity of cooling plate 46 can be regulated bycontrolling the current supplied to Peltier device 14, which can hencecontrol a freezing speed.

In this exemplary embodiment, a driving time of water pump 11 is soadjusted that it supplies the water of an amount that rises 0.5 mm inwater level inside ice-making vessel 43 at each operation for a totalnumber of 20 water-supply operations. A temperature surroundingice-making vessel 43 is influenced by the temperature of secondrefrigerator compartment 37, and it usually remains at a comparativelyhigh temperature. However, the temperature surrounding ice-making vessel43 is regulated to approximately 0 deg-C., when necessary, with a heater(not shown) disposed inside insulation wall 4 above ice-making vessel 43between second refrigerator compartment 7 and ice-making compartment 5.This can help the ice to develop only from the bottom surface. Inaddition, an amount of the current supplied to Peltier device 14 is soadjusted as to maintain cooling plate 46 to such a temperature thatmakes the freezing speed constant to bring the supplied water intofrozen in a two-hour duration.

Moreover, the driving time intervals of water pump 11 are so adjustedthat it starts supplying subsequent amount of water before water of theprevious supply becomes completely frozen.

A driving interval of water pump 11 is adjusted in a manner so that itsupplies the subsequent amount of water before the previously suppliedwater becomes completely frozen.

When a predetermined time duration “t” has elapsed after water pump 11has operated for the predetermined number of times (STEP 4), temperaturesensor 55 disposed to ice-making vessel 43 checks whether temperature Tibeing monitored becomes below a predetermined temperature (STEP 5), anddetermines completion of the ice-making operation (STEP 6). The swingingoperation is ended upon completion of the ice-making operation (STEP 7).When an amount of ice in ice storage box 15A is detected to be less thana predetermined amount (STEP 8), a current of the opposite direction issupplied to Peltier device 14 (STEP 9) to raise the temperaturemonitored by temperature sensor 55 to a level higher than thepredetermined temperature (STEP 10). The problem of ice getting stuck oncooling plate 46 is thus dissolved by melting the ice slightly in thismanner.

Driving mechanism 53 is operated thereafter to turn ice-making unit 300and ice-cracking unit 400 upside down (STEP 11), and to rotate twoshafts 48 simultaneously only by a predetermined angle by means of gearunit 50 of ice-cracking unit 400 (STEP 12).

When shafts 48 are rotated, there occurs a turning force imposed on theice block in a way to rotate with shafts 48. Since the side walls ofice-making vessel 43 restrict such a turning movement of the ice block,the turning force produces concentration of stresses imparted to the iceblock via ribs 48A of shafts 48, which in turn produces cracks in theice block from around shafts 48 toward outer walls of ice-making vessel43, and cracks the plank-shaped block of ice into a plurality ofirregularly-shaped chips without round edges. The cracked chips of icethus fall as they are into ice storage box 15A.

When shafts 48 end their rotary motion, driving mechanism 53 returnsice-making unit 300 and ice-cracking unit 400 into the originalhorizontal position (STEP 13), and gear unit 50 brings shafts 48 intothe original positions (i.e., starting points) (STEP 14). During thisoperation, shafts 48 can be returned to their original positions byrotating them in a direction opposite the direction where they arerotated when the ice block is cracked. In this exemplary embodiment,however, shafts 48 are rotated past their starting positions at once,and rotated again in the direction of cracking the ice block beforestopping at the starting positions.

Or, after the rotation (in STEP 12), shafts 48 may be driven again for apredetermined time (e.g., 5 seconds), and so arranged thereafter thattheir positions become starting positions designated in advance.Afterwards, ice-making unit 300 is returned to the horizontal position.

Following the above steps, a positive current is supplied to Peltierdevice 44 (STEP 15), and the operation returns to the start ofice-making control (STEP 1).

In ice-making device 100 of this third exemplary embodiment, asdescribed above, the plank-shaped block of ice positively falls into theice storage box as soon as it is cracked, because the ice-making unit ispositioned upside down when the block of ice is being cracked. Thisice-making device can thus provide irregularly-shaped pieces of icewithout having rounded edges, and sensually excellent for use inbeverages such as whiskey and water.

In addition, this structure can reduce to the utmost a time differenceamong the plurality of shafts to transfer the forces of the shafts tothe block of ice attributable to the play of the transmission gearsamong the shafts, since the shafts are rotated to the direction ofcracking the ice before coming to the stop when they are returned to thestarting positions. As a result, the plurality of shafts can properlytransfer their individual forces to the block of ice to crack itpositively.

In this structure, the shafts are rotated for the predetermined timeeven after the block of ice is cracked. This structure makes good use ofthe shafts to separate the ice stuck on the ice-making unit, so as tohelp remove the ice easily.

The structure also takes an advantage of heating the cooling platebefore the ice block is cracked to avoid the ice from sticking to it.This feature facilitates cracking of the ice block with a considerablysmall torque. It can also reduce finely crushed fragments of ice whichare not useful.

It also prevents the once frozen ice from being melted and makingrefreezing necessary, since it does not advance the subsequent steps ofheating the cooling plate unless the ice contained in the ice storagebox is found to be less than the predetermined amount. This can alsoensure the ice storage box to store more amount of ice than necessary.

If the ice storage box contains more ice than the predetermined amount,this device keeps the cooling plate at a temperature below zero topreserve the newly-made ice in the ice-making vessel, so that it canreplenish the ice storage box as soon as the ice is consumed to a levelbelow the predetermined amount.

In the process of ice-making according to this exemplary embodiment, thewater is gradually frozen upward from the bottom of ice-making vessel 43of ice-making unit 300. There is also a thin layer of unfrozen state ofwater maintained at all the time since the water is suppliedintermittently. This helps the air dissolved in the water to become airbubbles and diffuse into the surrounding air, and thereby the device canproduce ice of high clarity.

In addition, this device repeats the motion of tilting and stoppingice-making vessel 43 while making ice, which continuously moves aboundary surface between the ice and water, separates air bubbles formedon the boundary surface by the flow of water, and facilitates the airbubbles to diffuse into the air around ice-making vessel 43 by their ownbuoyancy. Accordingly, this device can produce the highly clear ice in acomparatively fast speed.

Once the cracked ice is released, this device restarts the nextwater-supply operation, but only after heating the ice-making unit to atemperature above the predetermined value. This process can prevent theice from losing the clarity in the bottom area due to rapid freezing ofthe supplied water, thereby making ice of even higher clarity.

In ice-cracking unit 400 used for cracking the plank-shaped block ofice, a torque required for shafts 48 to crack the ice can be obtainedeasily with any ordinary DC motor. This means the compact ice-crackingunit can be realized in a small size at low cost.

Fourth Exemplary Embodiment

Description is provided of ice-making device 100 of the fourth exemplaryembodiment with reference to FIG. 11.

Like reference numerals are used to designate like components as thoseof the third exemplary embodiment, and details of them will be skipped.FIG. 11 is a flow chart showing a main part among a number of controloperations of ice-making device 100 performed by a control unit (notshown) according to this invention.

Description from STEP 1 to STEP 12 will be skipped since they are sameprocesses as those described in the third exemplary embodiment.

When shafts 48 are rotated, there occurs a turning force imposed on ablock of ice in a way to rotate with shafts 48. However, the side wallsof ice-making vessel 43 restrict such a turning movement of the iceblock. This results in concentration of stresses imparted to the iceblock via ribs 48A of shafts 48, which in turn produces cracks in theice block from around shafts 48 toward outer walls of ice-making vessel43, and cracks the plank-shaped block of ice into a plurality ofirregularly-shaped chips without round edges. The cracked chips of icethus fall as they are into ice storage box 35A.

When the ice block is completely cracked, gear unit 50 returns shafts 48to the original positions (i.e., starting points) (STEP 13).

During this moment, pieces of ice stuck on shafts 48 and not releasedinto ice storage box 35A are shaken by rotation of shafts 48, anddisengaged to fall in the box below.

Afterwards, driving mechanism 53 returns ice-making unit 300 andice-cracking unit 400 to the horizontal position (STEP 14).

Peltier device 44 is then supplied with a positive current (STEP 15),and the operation returns to the start of ice-making control (STEP 1).

In ice-making device 100 of this fourth exemplary embodiment, asdescribed above, the plank-shaped block of ice positively falls into theice storage box as soon as it is cracked, because the ice-making unit ispositioned upside down when the block of ice is being cracked.

In addition, the device drives the shafts to shake the cracked ice whenthe shafts are returned to their original positions while the ice-makingunit is kept upside down, even if the cracked ice stick to any of theshafts and the ice-making vessel without falling. Since the structurereleases the cracked chips of ice from being stuck and allow them tofall more positively in the described manner, it can provideirregularly-shaped chips of ice without having rounded edges, andsensually excellent for use in beverages such as whiskey and water.

Fifth Exemplary Embodiment

Description is provided of ice-making device 100 of the fifth exemplaryembodiment with reference to FIG. 12.

Like reference numerals are used to designate like components as thoseof the fourth exemplary embodiment, and details of them will be skipped.FIG. 12 is a flow chart showing a main part among a number of controloperations of ice-making device 100 performed by a control unit (notshown) according to this invention.

Description from STEP 1 to STEP 10 will be skipped since they are sameprocesses as those described in the fourth exemplary embodiment.

Gear unit 50 drives and rotates two shafts 48 simultaneously up to apredetermined angle (STEP 11). When shafts 48 are rotated, there occursa turning force imposed on a block of ice in a way to rotate with shafts48. However, the side walls of ice-making vessel 43 restrict such aturning movement of the ice block, which results in concentration ofstresses imparted to the ice block via ribs 48A of shafts 48, which inturn produces cracks in the ice block from around shafts 48 toward outerwalls of ice-making vessel 43, and cracks the plank-shaped block of iceinto a plurality of irregularly-shaped chips without round edges.

Driving mechanism 53 is operated thereafter to turn ice-making unit 300and ice-cracking unit 400 upside down (STEP 12). During this operation,the cracked chips of ice fall as they are into ice storage box 35A bytheir own gravity since they are separated off the walls of ice-makingvessel 43 due to the heating and cracking operations.

Gear unit 50 returns shafts 48 to their original positions (i.e.,starting points) (STEP 13).

During this moment, pieces of ice stuck on shafts 48 and not releasedinto ice storage box 35A are shaken by rotation of shafts 48, anddisengaged to fall in the box below.

Afterwards, driving mechanism 53 returns ice-making unit 300 andice-cracking unit 400 to the horizontal position (STEP 13), and gearunit 50 also returns shafts 48 to their original positions (i.e.,starting points) (STEP 14).

Peltier device 44 is then supplied with a positive current (STEP 15),and the operation returns to the start of ice-making control (STEP 1).

As described above, ice-making device 100 of this fifth exemplaryembodiment turns the ice-making unit upside down only after it cracksthe block of ice, and thereby it does not cause loud sound, which couldoccur by ice chips dropping wildly into the ice storage box as they arebeing cracked. The device can hence provide irregularly-shaped chips ofice without having rounded edges, and sensually excellent for use inbeverages such as whiskey and water.

Sixth Exemplary Embodiment

Description is provided of ice-making device 100 of the sixth exemplaryembodiment with reference to FIG. 13.

Like reference numerals are used to designate like components as thoseof the fifth exemplary embodiment, and details of them will be skipped.FIG. 13 is a flow chart showing a main part among a number of controloperations of ice-making device 100 performed by a control unitaccording to this invention. Description from STEP 1 to STEP 12 will beskipped since they are same processes as those described in the fifthexemplary embodiment.

When a turning operation is completed, gear unit 50 returns shafts 48 totheir original positions (i.e., starting points) (STEP 13).

During this moment, pieces of ice stuck on shafts 48 and not releasedinto ice storage box 35A are shaken by the rotation of shafts 48, anddisengaged to fall in the box below.

Afterwards, driving mechanism 53 returns ice-making unit 300 andice-cracking unit 400 to the horizontal position (STEP 14).

Peltier device 44 is then supplied with a positive current (STEP 15),and the operation returns to the start of ice-making control (STEP 1).

As described above, ice-making device 100 of this sixth exemplaryembodiment turns the ice-making unit upside down only after it cracksthe block of ice, and thereby it does not cause loud sound, which couldoccur by ice chips dropping wildly into the ice storage box as they arebeing cracked.

Furthermore, since the device returns the shafts to their originalpositions while the ice-making unit is kept upside down, it shakes thecracked ice by the rotation of the shafts, and thereby it can releasethe cracked chips of ice from being stuck and allow them to fall morepositively. The device can hence provide irregularly-shaped chips of icewithout having rounded edges, and sensually excellent for use inbeverages such as whiskey and water.

Seventh Exemplary Embodiment

Description is provided of an ice-making device of the seventh exemplaryembodiment with reference to FIG. 14 and FIG. 15.

Ice-making device 800 comprises ice-making unit 801, insulatingmaterials 802 and 803 enclosing ice-making unit 801, andswinging-turning unit 804. Swinging-turning unit 804 is provided withdrive shaft 805. Ice-making unit 801 comprises ice-making vessel 806having an open bottom, and cooling plate 807 for composing a bottomsurface of ice-making vessel 806.

Cooling plate 807 is provided with fin-shaped cooling accelerate member808, and cooling plate 807 and cooling accelerate member 808 are formedintegrally.

Ice-cracking unit 809 is disposed underneath ice-making device 800.

Ice-cracking unit 809 comprises ice-cracking plates 810 and 811, andice-cracker drive unit 812.

The ice-making device constructed as above operates in a manner which isdescribed hereinafter.

Ice-making unit 801 of ice-making device 800 disposed in a freezingatmosphere is supplied with a predetermined amount of water from theabove by water supply means. The water supplied in ice-making unit 801starts being frozen from the lower side by cooling plate 807 and coolingaccelerate member 808. There is a heating means (not shown) locatedabove ice-making device 800, and the heating means together withinsulating materials 802 and 803 maintain the surrounding space ofice-making unit 801 at a non-freezing temperature of not lower than 0deg-C.

The operations of these components make ice to grow upward from thelower side, discharge air bubbles inside the water toward the unfrozenwater, and eventually release them into the atmosphere above the watersurface. Release of the air bubbles is not impeded since the water nearthe surface is kept from being frozen by the heating means andinsulating materials 802 and 803. As a result, the device can produceclear cubes of ice while limiting amount of air bubbles contained in thefrozen ice.

Swinging-turning unit 804 is kept operating during the ice-makingprocess for swinging motion of predetermined cycle and swinging angleabout drive shaft 805. This motion moderately stirs the water inice-making unit 801 to promote degassing of the water.

When detection means detects completion of the ice-making,swinging-turning unit 804 turns itself upside down about drive shaft 805to drop the block of ice from ice-making unit 801. The solid block ofice made in ice-making unit 801 is defined as ice block 813.

Ice-cracking unit 809 disposed under ice-making device 800 hasice-cracking plates 810 and 811 in an open position to an angle ofapproximately 90 degrees, and ice block 813 falls on ice-cracking plate811.

Next, ice-cracker drive unit 812 turns, and this motion rotatesice-cracking plate 810 in the closing direction. Ice-cracking plate 811is kept not rotated during this process so that ice block 813 is pressedbetween ice-cracking plates 810 and 811, and cracked into dimensionssuitable for practical use.

After the ice block 813 is cracked, ice-cracking plate 811 rotatesdownward to drop the cracked pieces of ice further downward.

Upon completing the series of operations, ice-cracking plates 810 and811 return to their original positions while maintaining the 90-degreeangle, and wait for the next block ice.

Although ice-cracking plates 810 and 811 were described as having theangle of approximately 90 degrees with respect to each other, they maybe opened to a 180-degree angle in the vertical orientation or eitherone of them may be shifted to same phase to the other, so as to allowthe ice block to drop directly from the ice-making unit for storage asit is.

In this case, the user can take the ice block of the original size forprocessing into any size of his choice, by using a commerciallyavailable ice crusher or an ice pick, for instance.

As described above, ice-making device 800 of this exemplary embodimentcomprises ice-making unit 801, insulating materials 802 and 803, andswinging-turning unit 804. Ice-cracking unit 809 is disposed underneathice-making device 800, and it comprises ice-cracking plate 810, anotherice-cracking plate 811, and ice-cracker drive unit 812. This combinationof ice-making device and ice-cracking unit 809 has capability ofcracking the block ice into small chips of suitable size while making ablock of clear ice simultaneously.

Eighth Exemplary Embodiment

Description is provided of an ice-making device of the eighth exemplaryembodiment with reference to FIG. 16 through FIG. 22.

Water pump 11 defining an intermittent water supply means supplies waterinside water tank 10 little by little in a plurality of steps toice-making unit 300 through water supply pipe 11A.

Ice-making unit 300 comprises ice-making vessel 503, cooling plate 16,and water sealing member 30 disposed in a space between outer flange503B of ice-making vessel 503 and cooling plate 16. There is alsoprovided ice-cracker drive unit 68 under cooling plate 16. Furthermore,heat sink 69 is provided under ice-cracker drive unit 68, and coolingmeans is placed between cooling plate 16 and heat sink 69. Cooling meanscomprises one or more units of Peltier device 14, for example. Fixingmember 60 is disposed on the periphery of Peltier device 14 for thepurpose of securing the position of Peltier device 14. In addition,water-infiltration sealing member 31 is placed in each of spaces betweencooling plate 16 and fixing member 60, and heat sink 69 and fixingmember 60, to prevent moisture from infiltrating in the vicinity ofPeltier devices from the outside. Both cooling plate 16 and heat sink 69are made of a material of good thermal conductivity such as aluminum.Supporting members 61 and 62 are integrally formed individually withrespective one of supporting brackets 63 and 64 having generally abox-like configuration with open end at one side. Ice-making vessel 503,cooling plate 16, water sealing member 30, ice-cracker drive unit 68,heat sink 69, Peltier device 14, fixing member 60 and water-infiltrationsealing members 31 are held between top and bottom by supportingbrackets 63 and 64.

In this structure, ice-making vessel 503 is pressed in the directions ofcooling plate 16 by supporting members 61 and 62, while also imposing amoderate compression on water sealing member 30.

One side of supporting member 62 has insertion opening 32 formedintegrally, and a driving shaft of swing drive unit 65 is insertedtherethrough. A plurality of shafts 66 connected to ice-cracker driveunit 68 penetrate through cooling plate 16 and extend in the directionof ice-making unit 300. Through-holes in cooling plate 16 are providedwith water sealing members 33 for sealing spaces around shafts 66. Watersealing members 33 are secured to cooling plate 16 by fixing plates 34.

Cooling plate 16 is provided with temperature detection means such astemperature sensor 35, and mounted to supporting member 61.

Supporting members 61 and 62 contain insulating materials 36 in them.Ice-making device 67 comprises ice-making vessel 503, cooling plate 16,water sealing members 30, ice-cracker drive unit 68, heat sink 69,Peltier device 14, fixing member 60, water-infiltration sealing member31, supporting member 61, supporting member 62, shafts 66, water sealingmember 33, fixing plates 34, temperature sensor 35 and insulatingmaterials 36, and they are secured to one another. Ice-making device 67is placed inside an ice-making compartment in a manner that its upperportion is housed in a space of generally a dome-shaped concaved portionformed in top surface 504 of the compartment. Supporting member 61 isclosely located to the concaved portion in top surface 504 of thecompartment to an utmost extent without interfering rotation ofice-making device 67 while minimizing circulation of the air throughice-making unit 300 and the ice-making compartment. Top surface 504 ofthe ice-making compartment is equipped with heating means (not shown)inside the concaved portion.

The automatic ice-making device constructed as above operates in amanner which is described hereinafter.

The water supplied by water pump 11 from water tank 10 through watersupply pipe 11A is stored in a space of ice-making unit 300 bounded byice-making vessel 503 and cooling plate 16. Ice-making vessel 503 has anopen bottom from where cooling plate 16 is exposed. The water stored inice-making unit 300 does not leak out because of water sealing member 30placed between ice-making vessel 503 and cooling plate 16. Water sealingmembers 33 disposed around shafts 66 also prevent the water from leakingout of ice-making unit 300. Water sealing members 33 are formed of arubber-like elastic material into an annular shape. These water sealingmembers 33 have one or more stages of fin-like configuration formedalong their inner perimeters, and their inner diameters are smaller thanthe outer diameter of shafts 66. Moreover, the inner perimeters of watersealing members 33 are coated with grease to further improve thewaterproofing property.

Supply of water to ice-making unit 300 is so controlled that water isfed little by little in number of divided steps rather than all at once,although it can hold 50 ml to 200 ml of water. The number of dividedsupplies and amount of water in each supply can vary depending on a sizeof ice block to be produced. In any case, a comparatively large amountof water is supplied in the first feeding, and the water is then reducedto a constant amount for the subsequent feedings.

The large amount of water is necessary for the first feeding in order toavoid clouds in the ice, since the water poured directly on coolingplate 16 for the first time is often chilled very rapidly, and it tendsto become white cloudy. The amount of water for the subsequent feedingsis so adjusted as to maintain a thin layer of unfrozen water on thesurface of ice. An optimum thickness of the water layer is determined sothat it helps the water to degas faster than the speed of freezing, andto remove the air of sufficient amount before the water becomes frozen.

To avoid the formation of clouds in the first supply of water, thesurface temperature of cooling plate 16 needs to be regulated in advanceto ensure a level higher than a predetermined temperature beforesupplying the water.

The ice is made in this manner by accumulating the amounts graduallyinside ice-making unit 300. A timing of the water supply is so set thatthe new supply of water is made before the previous supply becomescompletely frozen.

The reason of this is to avoid formation of a cloud layer in the ice dueto the frost developed on the surface of ice from the previous supply ofwater if the water becomes completely frozen before new supply is made.The subsequent supplies of water are necessary before the water surfacebecomes completely frozen to realize an integral block of clear ice.

Peltier device 14 is in contact with a protruding part extending undercooling plate 16, and it cools cooling plate 16. Cooling plate 16 usedhere is made of a metallic plate of good thermal conductibility such asaluminum, and it has a thickness of 2 mm to 15 mm to obtain evenness oftemperature throughout the cooling surface. Use of this structure allowsa certain degree of flexibility in the arrangement of Peltier device 14.

The supplied water freezes gradually from the bottom side of coolingplate 16 while dispelling gaseous components in the water upward. On theother hand, a space surrounding ice-making unit 300 is thermallyisolated by insulating materials 36 from the inner air of the ice-makingcompartment and heated by the heating means on top surface 504 of theice-making compartment, which keep the ambient temperature aroundice-making unit 300 higher than 0 deg-C. The top surface of the suppliedwater thus remains free from freezing. In this instance, ice-makingvessel 503 may be heated directly by another heating means to obtain thelike advantageous effect, instead of using the heating means disposed tothe concave portion in top surface 504 of the ice-making compartment.

Temperature sensor 35 keeps monitoring the temperature of cooling plate16, and performs control of the optimum freezing speed by properlyregulating a voltage to Peltier device 14. In the case that the freezingspeed is faster than the speed of degassing, for instance, the voltageto Peltier device 14 is regulated to raise the temperature of thecooling surface. If the freezing speed is slower, on the other hand, thevoltage to Peltier device 14 is regulated so as to decrease thetemperature of the cooling surface.

The ice grows upward into a convex shape as the time elapses after thestart of ice making, and a distance of the frozen surface from coolingplate 16 also increases proportionally.

As a result, the grown ice itself has an effect of thermal insulation,which impedes conduction of the freezing effect. This fact necessitatesgradual lowering of the temperature of the cooling surface in order tomaintain the same freezing speed on the frozen surface. Such a controlof the freezing speed can be achieved by gradually decreasing thevoltage to the Peltier device with elapse of the time.

When this ice-making device 67 is disposed inside an ice-makingcompartment or a freezer compartment of a refrigerator, there is a casethat the freezing speed becomes too fast in the initial stage ofice-making because of the effect of the surrounding temperature. In thiscase, the polarity of voltage applied to Peltier device 14 is reversedto heat the cooling surface for a given time duration from the start ofice-making in order to optimize the freezing speed. Subsequently, thepolarity of voltage is reversed again after the given time has elapsed,to start the cooling of the cooling surface until the ice making iscompleted. When the polarity of the voltage is reversed, it is desirableto provide an interruption of the power supply for a certain time periodfor the sake of maintaining reliability of the useful life of Peltierdevice 14.

When the ice making is found started, swing drive unit 65 beginsswinging ice-making device 67, which causes the supplied water insideice-making unit 300 to flow smoothly across the ice surface from theupper side to the lower side by the force of gravity in response to thetiming of inclination of ice-making unit 300. The ice surface becomeswet by the surface tension of water after the water flows therethrough,and thereby leaving an extremely thin layer of the water as observedmicroscopically. The swinging motion also stirs the water moderately,and expedites the degassing. The presence of the extremely thin layer ofwater substantially reduces the distance for air in the water to reachthe boundary to the atmospheric air, and helps expediting the degassing.

Clarity of the ice produced in ice-making vessel 503 changes dependingon the swinging angle. FIG. 21 is a result of examination showinginfluence upon the clarity when the swinging angle is changed. As shownin FIG. 21, the clarity improves sharply as the swinging angle isincreased up to about 10 degrees. This improvement of the claritybecomes blunt, however, when the angle exceeds 10 degrees. The suppliedwater tends to overflow from ice-making vessel 503 if the swinging angleis increased excessively. It is thus considered very appropriate todesign the swinging angle of ice-making vessel 503 within a range of 10to 20 degrees.

Clarity of the ice produced in ice-making vessel 503 also changesdepending on the swinging frequency. FIG. 22 is a result of examinationshowing influence upon the clarity when the swinging frequency ischanged. As shown in FIG. 22, the clarity improves as a number ofswinging cycles increases. The improvement of the clarity saturates,however, when the number is too many.

The reason of this is considered to be the fact that the excessivenumber of swinging cycles prevents the supplied unfrozen water frommoving between one side to the other side of the ice-making vessel, butkeeps the water to wave only in an area around the center of the vessel,thereby limiting movement of the water over the boundary of the icesurface.

This results in reduction of the gravitational effect of moving thewater and loss of improvement in the clarity. On the other hand,produced ice gets a trace of white cloud attributable to partialfreezing of the water near the boundary of the ice if the number ofswinging cycles is too small. Swinging rates of 3 to 10 cycles perminute are considered suitable for improvement of the clarity. The watersupplied in ice-making vessel 503 is freely movable across an entirewidth thereof since there is no wall in ice-making unit 300 that isgenerally perpendicular to the swinging direction. A movable distance ofthe supplied water in the example of this exemplary embodiment of theinvention is substantially large as compared to the conventionalice-making vessel, which is normally divided into a plurality ofsections.

However, the movable distance of the water may not be consideredsufficient if sidewalls 503A of ice-making vessel 503 areperpendicularly formed with respect to the cooling surface. In addition,a growth rate of ice becomes somewhat faster along sidewalls 503A ascompared to the center area due to heat conduction and surface tensionalong sidewalls 503A. For the above reason, there are often cases thatwhite cloud appears in the center area along the swinging axis due tolinearly formed air bubbles inside the ice block, when produced in anice-making vessel having sidewalls 503A of perpendicular configuration.

It is for this reason that ice-making vessel 503 is so shaped thatsidewalls 503A are sloped in a manner to gradually increase the surfacearea of ice toward the perpendicular direction from the cooling surface,in order to ensure a large movable distance for the water. The sidewallsof such configuration can also alleviate the influence of thermalconduction from the cooling surface. Therefore, the ice is made to growaround the center area of the swinging axis, that is the center of theice-making vessel, to prevent the water from remaining unfrozen in thecenter area.

Moreover, the angle of slope influences the shape of the ice-makingdevice. This is because a dimension of the sidewalls becomes larger withincrease in angle of the slope, in order to maintain a certain thicknessof the ice block. This influences the turning locus of ice-making unit300 including ice-making vessel 503 when releasing ice, configurationsof top surface 504 of the ice-making compartment and supporting members61 and 62, as well as an overall volume of the entire ice-making device.An angle in the range of 10 to 30 degrees is thus determined suitablefor the slope of the sidewalls of ice-making vessel 503. Any anglewithin this range can ensure the clarity of produced ice blocks whilealso prevent the water from overflowing the ice-making vessel.

The ice-making vessel of this invention as illustrated in this eighthexemplary embodiment has such configuration that sidewalls 503A are bentinward at areas exceeding the designed height of ice blocks. Thisconfiguration can reduce the turning locus of ice-making vessel 503 whenit swings and releases the produced ice, and downsize ice-making device67. Beside the above, the pause time at the largest swing angle also hasa significant meaning in determining the swinging frequency. In otherwords, the pause time at the largest swing angle ensures the timerequired for the unfrozen water to move from one side wall to the other.It is therefore considered appropriate to provide a range of 3 to 7seconds as a flow time for movement of the unfrozen water from side toside, while maintaining the water not becoming frozen on the ice surfaceat the same time.

It may be advisable to use these fact as specifications for the controlof swinging frequency.

Ninth Exemplary Embodiment

Description is provided of the ninth exemplary embodiment with referenceto FIG. 16 and Tables 1A through 1G.

Like reference numerals are used to designate like components as thoseof the eighth exemplary embodiment, and details of them will be skipped.

Water pump 11 functioning as an intermittent water supply meanscomprises a tube pump driven by a stepping motor. The stepping motorruns at a constant rotational speed responsive to a pulse rate, withoutbeing affected to a certain extent by variations in the supply voltage.The tube pump has a good advantage because of its inherentcharacteristic that accuracy of displacement is very high so long as thespeed of a roller for squeezing a tube is kept constant. A result ofthese is the high water-supply accuracy when used to controlintermittent supply of water. On the other hand, gear pumps and impellerpumps receive serious influences from variations in resistance of watersupply channels and passages, although they are used for ice-makingdevices in general because of their advantage of comparatively low cost.Gear pumps and impeller pumps are therefore not so suitable for watersupply of small amount because of the low water-supply accuracy asopposed to tube pumps.

The ice-making device having the above structure operates in a manner aswill be described hereinafter.

When a temperature sensor detects a temperature of cooling plate 16 asbeing within a predetermined temperature range, water pump 11 operatesfor a certain number of steps to supply a predetermined amount of waterto ice-making unit 300. At the same time, swing drive unit 65 startsswinging ice-making unit 300. The swinging operation is repeated at apredetermined swing cycle until the ice making is completed.

After the first supply of the predetermined amount water, water pump 11takes a pause of a predetermined period, restarts again to supplyanother predetermined amount of water to ice-making unit 300, takesanother pause of the predetermined period, and restarts again to supplythe predetermined amount of water. Water pump 11 repeats theintermittent water supply until water of a predetermined amount issupplied to ice-making unit 300. When the water supply is completed, thestepping motor operates water pump 11 in the reverse direction toretract the water left inside water supply pipe 11A and return it intowater tank 10.

To make ice of high clarity, it is necessary to keep the speed of airbubbles to escape from the unfrozen water to the surrounding air thanthe freezing speed.

In the ice-making device of this exemplary embodiment, the freezingspeed of water at various thickness of the ice during the process ofice-making affects substantially to the clarity of ice, because the icegrows upward from the bottom generally in two dimensionally. It istherefore effective to slow down the freezing speed to make ice ofbetter clarity. In view of convenience for the user, on the other hand,it is desirable to make an ice block of appropriate thickness within theshortest possible time, and sufficient consideration needs to be givenon the intended thickness of the finalized ice, and the ice-making timeto complete the ice block of desired thickness. It is quite difficult tocontrol the freezing speed since the freezing speed decreases graduallywith increase in thickness of the ice due to the ice acting as aresistance against thermal conduction of the cooling plate, if a coolingcapacity of the cooling plate is kept constant. In this exemplaryembodiment, the ice-making device is equipped with Peltier device 14 asa cooling source of cooling plate 16.

A cooling capacity of Peltier device 14 is variable by means of changingthe supply current to it, and this realizes such control as to obtainthe optimum freezing speed at any point of varying thickness of the ice.

Here, ice-making unit 300 is swung during the ice making to move thewater on the boundary of ice in order to promote the release of airbubbles into the surrounding atmosphere. As stated, the width and theswinging angle of ice-making unit 300 substantially influence theclarity of ice as the water is moved by the swinging motion in thedirection perpendicular to the swinging axis. Additionally, what isimportant among the factors in the swinging cycle that influence theclarity of ice is a time to pause the ice-making unit while beingtilted. This reason is clear because the purpose of the swinging motionis to flow unfrozen water over the surface of ice to separate adhesionof air bubbles formed on the boundary of the water and the ice.

When ice-making unit 300 is paused while kept tilted during the swingingcycle the unfrozen water flows on the surface of ice, and this exposes apart of the ice surface. However, the intermittent supply of waterrecovers the entire ice surface wet once the water is flown over it.Since the extremely thin layer of water can be produced in this manner,this helps shorten the distance for the air bubbles to get released andexpedite the degassing. Accordingly, the amount of water supplied eachtime and supply intervals greatly influence the clarity in thisintermittent water supply.

Table 1 shows the result of experiments performed on the ice-makingdevice of this exemplary embodiment, in which changes in the clarity arechecked while changing total amount of supplied water (i.e., thicknessof ice), bottom width of ice-making vessel, number of divided watersupplies, amount of each water supply, swinging angle, swinging cycle,and ice-making time.

In these experiments, sidewalls of the ice-making vessel were sloped sothat a surface area increases gradually toward the upper directionperpendicular to the bottom surface. Because of this slope, an increasein depth of water supplied over the ice surface decreases gradually asthe number of water supplies accumulates even when water of the sameamount is supplied each time at the same interval.

The swinging cycle was so adjusted that the ice-making unit movesapprox. 1 second to make a full swing of the predetermined angle, andstays paused at the tilted position for the remainder of the time. Whena condition was given that the swinging angle is ±15 degrees at theswinging cycle of 5 cycles/minute, for example, one cycle consisted of 1second for the swing of 30 degrees from −15 to +15 degrees, 5 seconds ofpause at the +15-degree position, 1 second for another swing of 30degrees from +15 to −15 degrees, and 5 seconds of another pause at the−15-degree position.

Although a greater effect is anticipated by increasing the swingingangle, it requires higher sidewalls of the ice-making vessel to avoidoverflow of the water from the sidewall during the pause period in whichthe ice-making unit is held tilted.

Since the ice-making device could become too large, the angle of tiltwas limited to 15 degrees.

In respect of the thickness of ice blocks, an evaluation was made withthe appropriate thickness considered to be easy to use in the standpointof users. If ice blocks are too thick, convenience of use is not so goodbecause cracked pieces of the ice become too large for use in smallglasses and the like containers. If ice blocks are too thin, on theother hand, their exterior appearance becomes poor and loose worthinessof use. Accordingly, thicknesses between 15 mm and 25 mm were used forthis evaluation.

In respect of the amount of water in the intermittent water supply, theamount for the first supply was determined to be somewhat more thanamount of the subsequent supplies, and that is sufficient to raiseapprox. 5 mm of water depth on the ice-making unit, to prevent it frombeing frozen quickly before spreading over the cooling plate.

The ice-making time was set to 120 minutes based on the time normallyrequired to make ice cubes by conventional ice-making device. In thiscase, the voltage supplied to the Peltier device was gradually changedand so adjusted that the freezing speeds does not vary excessively atpoints of varying ice thicknesses, and none of the freezing speeds isextremely fast. The evaluation was also made under the conditions inwhich the ice-making time exceeds 120 minutes in consideration of theimportance on the clarity of ice blocks.

In this evaluation for the experimental results, the clarity of iceblocks were classified into four levels of quality: “A” for excellentlevel of clarity with very little apparent cloudiness (good clarity over90% of the overall volume of the ice block); “B” for high level ofclarity with little apparent cloudiness (good clarity over 70% but notexceeding 90% of the overall volume of the ice block); “C” for fairlevel of clarity with sporadic apparent cloudiness, satisfactorilyuseable as compared to ice blocks made by ordinary ice-making device(clarity over 50% but not exceeding 70% of the overall volume of the iceblock); and “D” for poor level of clarity with similar degree ofcloudiness as ice blocks of ordinary ice-making device (clarity notexceeding 50% of the overall volume of the ice block). Any of ice blocksclassified “B” or above is regarded as relatively high clarity andsensually excellent.

The classifications of “A”, “B”, “C” and “D” represent “excellent”,“good”, “fair” and “poor” respectively. The expression of “±15 deg”means a swing motion consisting of a 15-degree movement in one direction(positive direction), and another 15-degree movement in the oppositedirection (negative direction).

Embodied sample 1 through 18 shown in Table 1A are the complete resultsof these experiments performed on the ice-making device of thisexemplary embodiment, in which changes in the clarity are checked whilechanging the total amount of supplied water (i.e., thickness of ice),bottom width of the ice-making vessel, number of divided supplies ofwater, amount of water at each supply, swinging angle, swinging cycle,and ice-making time. Table 1B through Table 1G show the relationsbetween different values of the individual factors and the clarities,and of their comparisons on the experiments as tabulated in Table 1A.Detailed results of these experiments will be given below.

Table 1B shows the result of experiment made to confirm whether clearblocks of ice can be made by changing only the ice-making time whenwater of a fixed amount is put in the ice-making vessel without makingswing motion and intermittent water supply.

This experiment was carried out by making ice blocks of 15 mm thick,which is considered the smallest limit in light of convenience for theuser side.

According to Table 1B, the ice block made within the 120-minute duration(sample 14) resulted in the clarity of “D” (the clarity not exceeding50% of the overall volume of the ice block) containing similar degree ofcloudiness as the ice block made with the ordinary ice-making device. Onthe other hand, the ice block made by cooling slowly in the timeduration of 240 minutes (sample 15) resulted in the clarity of “C” forthe satisfactory level of clarity (the clarity over 50% but notexceeding 70% of the overall volume of the ice block) as compared to iceblocks made by ordinary ice-making device although it had white cloudssporadically. However, this method would require a substantially longhours for a thick block of ice, since it needed the 240 minutes of longtime to make the ice block of the smallest thickness of 15 mm. It wasknown that ice block of only fair clarity is obtainable even if manyhours are spent for it. Further improvement is thus needed because it ispreferable to obtain an ice block of good clarity in about 120 minutesin consideration of the user's needs.

Table 1C shows the result of experiment made to check the clarity byvarying the thickness of ice blocks made with swing motion under certaincondition, but without making intermittent water supply.

According to Table 1C, the ice block having 15 mm in thickness (sample13) was made with sufficiently good clarity at the level “B” (goodclarity over 70% but not exceeding 90% of the overall volume of the iceblock) although it showed small number of white clouds locally. However,the clarity was found decreased gradually with the increase in thicknessof the ice block to 20 mm (sample 6) and 25 mm (sample 16).

Table 1D shows the result of experiment made to check the clarity of iceblocks made by varying the width of the bottom surface of the ice-makingvessel in the direction perpendicular to the swing axis while makingswing motion and intermittent water supply under certain condition.

According to Table 1D, the ice block made with the ice-making vessel of40 mm in the bottom width (sample 2) resulted in the clarity level “C”having enough clarity (the clarity over 50% but not exceeding 70% of theoverall volume of the ice block) as compared to ice blocks made byordinary ice-making device although it contained white cloudssporadically.

The ice block made with another ice-making vessel having the bottomwidth extended to 60 mm (sample 3) resulted in the clarity level “B”with sufficiently good clarity (the good clarity over 70% but notexceeding 90% of the overall volume of the ice block) although it showedsmall number of white clouds locally. This result was attributable tothe wide bottom surface of the ice-making vessel which gave a largedistance for the water to move during the swing motion, and to expeditethe degassing in the water, which in turn improved the clarity. It washence determined that improvement of the clarity is possible by furtherextending the width of the ice-making vessel. Additional experiment wasalso made with an ice-making vessel having a bottom width of 80 mm,although not shown in Table 1D. The result showed that the wateroverflows under the same swing condition unless the height of theice-making vessel is raised considerably. It was thought to be difficultto increase the width of the ice-making vessel to 80 mm in considerationof the restrictions in design of domestic refrigerators, since theice-making vessel takes a large space when making a turning motion everyafter the end of ice-making.

Table 1E shows the result of experiment made to check the clarity of iceblocks made by varying only the swinging angle while maintaining thesame swinging cycle and the intermittent water supply under certaincondition.

According to Table 1E, the ice block made with the swinging angle of ±5degrees (sample 8) resulted in the clarity of “D” containing similardegree of cloudiness as the ice block made with the ordinary ice-makingdevice (the clarity not exceeding 50% of the overall volume of the iceblock). The clarity improved to level “C” when the swinging angle wasincreased to ±10 degrees (sample 7), and to level “B” when the swingingangle was ±15 degrees (sample 3). It was thus known that the clarity canbe improved by increasing the swinging angle. Additional experiment wasalso made with the swinging angle of ±20 degrees, although not shown inTable 1E. The result showed the water overflows under the same swingcondition unless the height of the ice-making vessel is raisedconsiderably. It is difficult to increase the swinging angle of theice-making vessel to 20 degrees within any domestic refrigerator due tothe restrictions in design.

Accordingly, it is considered preferable to maintain the swinging anglein the range of 10 degrees to 20 degrees to avoid bulkiness of theice-making device as previously stated, though large effect may beanticipated with large swinging angle.

Table 1F shows the result of experiment made to check the clarity of iceblocks made by varying the swinging cycle while maintaining the sameswinging angle and the intermittent water supply under certaincondition.

According to Table 1F, the ice block made with the swinging cycle of 2cycles/min (sample 9) resulted in the clarity of “D” containing similardegree of cloudiness as the ice block made with the ordinary ice-makingdevice (the clarity not exceeding 50% of the overall volume of the iceblock). It is thought that this is attributable to deficiency of thedegassing because of stagnation in the flow of water during the swingingmotion. The ice block of clarity level “B” was achieved when theswinging cycle was increased to 5 cycles/min (sample 3) withsufficiently good clarity (the good clarity over 70% but not exceeding90% of the overall volume of the ice block) although it showed verysmall number of white clouds locally. The clarity decreased to level “C”when the swinging cycle was increased to 10 cycles/min (sample 17), andfurther to level “D” when the swinging cycle was increased 15 cycles/min(sample 10). The clarity of the ice blocks decreased as stated abovewhen the swinging cycle was increased excessively. The reason of suchdecrease may be the fact that the water is unable to move a sufficientlylong distance due to the short pause period in the tilted position whichprevents the water from flowing across the ice surface in one directionbefore the ice surface starts tilting to the opposite direction. As aconsequence, this does not allow the water to flow over the ice surfaceof enough distance, thereby preventing sufficient degree of degassing.

It was known accordingly that there are optimum ranges and conditions inthe swinging cycle in relation with configuration of the ice-makingvessel and amount of the water supply, and ice blocks of high clarityare producible only by way of controlling the swinging cycle within theoptimum ranges.

Table 1G shows the result of experiment made to check the clarity of iceblocks made by varying the number of divided water feedings within thesame ice-making time while maintaining the swinging operation undercertain condition.

According to Table 1G, the ice block made with only a single supply ofwater (sample 6), rather than dividing the supply of water (i.e.,intermittent water supply) resulted in the clarity level of “C” showingthe satisfactory level of clarity (the clarity over 50% but notexceeding 70% of the overall volume of the ice block) as compared to iceblocks made by ordinary ice-making device although it contained whiteclouds sporadically.

When the ice block was made with the supply of water divided into 10times (sample 5), on the other hand, the clarity was improved to level“B”. The same high clarity level “B” was also achieved for the ice blockmade with the supply of water divided into 20 times (sample 3). This isbelieved to be attributable to the intermittent supply of water and theswinging operation, that the swinging motion can move the small amountof water effectively to help expedite the degassing in the water.

The clarity of the ice block was decreased to the level “C” when thenumber of divided water supplies was further increased to 30 times(sample 18), and to the level “D” for anther ice block if the number wasincreased to 40 times (sample 4), indicating the tendency ofdegradation. This phenomenon is thought to be the following. Theincrease in number of the divided supplies of water can help move alesser amount of the water in the swinging motion to expedite thesufficient extent of degassing from the water. If the amount of thewater is excessively small, however, the water tends to start freezingimmediately after supplied, and it often becomes completely frozenbefore the subsequent supply of water. As the consequence, when thismakes a complete frozen surface between the preceding and the succeedingsupplies of water, the frozen surface remains cloudy in a form of thinlayer when observed from the side of it, for instance. This is thephenomenon that reduces the clarity. As stated, the phenomenon ofcloudiness develops for the different reason from that of the case withless number of divided water supplies. In order to avoid this layer ofcloudiness, it is necessary to cover the frozen surface with water atall the time by feeding a new supply of water before the previouslysupplied water becomes frozen.

Accordingly, it was known that there are optimum ranges in the number ofdivided supplies of water in relation with the swinging conditions, theice-making time and the like, and ice blocks of high clarity areproducible only by way of controlling the number of divided supplieswithin the optimum ranges.

In brief, it was understood that the ice blocks of high clarity can beproduced by controlling the number of divided supplies (i.e.,intermittent water supply) as well as mutually related factors among theswinging cycle, swinging angle and the like upon determination of theallowable dimension of the bottom width in design of the ice-makingvessel, when the making the ice blocks within the shortest timepossible.

According to this exemplary embodiment, the optimum number of dividedsupplies of water can be in a range of 10 to 20 times for an ice-makingdevice having an ice-making vessel with a bottom width of approx. 60 mm,provided that the ice-making time is 120 minutes, swinging angle isapprox. ±15 degrees, and swinging cycle is about 5 cycles/min (samples 3and 5). These conditions could provide ice blocks of clarity level “B”which have sufficiently good clarity although it showed very smalltraces of white clouds (the good clarity over 70% but not exceeding 90%of the overall volume of the ice block).

When the ice-making time is increased to twice as long as 240 minutesunder the same conditions as above, the result was an ice block with theclarity level “A” (good clarity over 90% of the overall volume of theice block) having very high level of clarity with very little apparentcloudiness (sample 11).

When the thickness of ice block is reduced to about 15 mm under the sameconditions as above (the conditions for samples 3 and 5), there was anice block of the clarity level “A” (good clarity over 90% of the overallvolume of the ice block) having very high level of clarity with verylittle apparent cloudiness. It was also found that an ice block of theclarity level “B” is producible without making the intermittent watersupply but only with the swinging operation (sample 13), if thickness isreduced to about 15 mm, the clarity of which is sufficiently goodalthough there were very small traces of white clouds (the good clarityover 70% but not exceeding 90% of the overall volume of the ice block).

In other words, clear ice blocks are producible, if their thickness isabout 15 mm, without employing an expensive water pump and the like forintermittent water supply, but only a less expensive ordinary water pumpused in the past. An ice-making device capable of producing clear iceblocks can be realized in this way at very low cost.

It was also found that ice blocks of comparatively high clarity can bemade with an ice-making device employing the water pump using arelatively inexpensive gear pump or impeller pump commonly used for theordinary ice-making device, even if thickness of the ice blocks is 15 mmor larger, provided that certain conditions such as the swingingoperation are arranged properly.

As described above, there are a variety of conditions that realize clearice blocks with the effect of the swinging motion so long as theice-making time is approx. 120 minutes and the thickness of the iceblocks is about 15 mm, although it depending on the ways of arrangingthe thickness and ice-making time.

It is also possible to produce ice blocks of even higher clarity byproviding the ice-making device with a special-purpose water pumpcapable of supplying a small amount of water.

It is also feasible to adopt a method of improving the accuracy ofsupplying water of a small amount using any of gear pump and impellerpump in which a resistance of water passage is intentionally increasedby reducing an outlet aperture of the pump to prolong the operating timeneeded for supply of the predetermined amount of water. Use of the abovemethod enable the intermittent water supply with a comparatively lowcost.

It should be understood that the samples discussed in this exemplaryembodiment are not intended to restrict the individual parameters. Theclarity of ice blocks can be improved in still many other ways byselecting suitable combinations.

Tenth Exemplary Embodiment

Description is provided of the tenth exemplary embodiment with referenceto FIG. 16 through FIG. 20.

Since an ice-making device of this exemplary embodiment has the samestructure as that of the eighth exemplary embodiment, details of it willbe skipped.

Water supplied by water pump 11 from water tank 10 through water supplypipe 11A is stored in a space of ice-making unit 300 bounded byice-making vessel 503 and cooling plate 16. Ice-making vessel 503 has anopen bottom from where cooling plate 16 is exposed. The water stored inice-making unit 300 does not leak out because of water sealing member 30placed between ice-making vessel 503 and cooling plate 16. Water sealingmembers 33 disposed around shafts 66 also prevent the water from leakingout of ice-making unit 300. Water sealing members 33 are formed of arubber-like elastic material into an annular shape. These water sealingmembers 33 have one or more stages of fin-like configuration formedalong their inner perimeters, and their inner diameters are smaller thanthe outer diameter of shafts 66. Moreover, the inner perimeters of watersealing members 33 are coated with grease to further improve thewaterproofing property.

Supply of water to ice-making unit 300 is so controlled that water isfed little by little in number of divided steps rather than all at once,although it can hold 50 ml to 200 ml of water. The number of dividedsupplies and amount of water in each supply can vary depending on a sizeof ice to be produced, and it may be arranged in a range of 5 times and25 times. In any case, a comparatively large amount of water is suppliedin the first feeding, and the water is then reduced to a constant amountfor the subsequent feedings.

The large amount of water is necessary for the first feeding in order toavoid the ice from getting cloudy due to the water being frozen veryrapidly when the small amount of water is supplied. The amount of waterfor the subsequent feedings is so adjusted as to maintain a thin layerof unfrozen water on the surface of ice. An optimum thickness of thewater layer is determined so that it helps the water to degas fasterthan the speed of freezing, and to remove the air of sufficient amountbefore the water becomes frozen. The ice is made in this manner byaccumulating the amount gradually inside ice-making unit 300. A timingof the water supply is so set that the new supply of water is madebefore the previous supply becomes completely frozen. The reason of thisis to avoid formation of a cloud layer in the ice due to frost developedon the surface of ice from the previous supply of water if the water iscompletely frozen before new supply is made. The subsequent supplies ofwater are necessary before the water surface becomes completely frozento realize an integral block of clear ice.

An ambient temperature in a space surrounding ice-making unit 300 iskept higher than 0 deg-C. since a concaved portion in top surface 504 ofthe ice-making compartment is heated by a heating means and the space isthermally isolated by insulating materials 36 from the inner air of theice-making compartment. In this instance, ice-making vessel 503 may beheated directly by another heating means to obtain the like advantageouseffect, instead of using the heating means disposed to the concaveportion in top surface 504 of the ice-making compartment. Peltier device14 is in contact with a protruding part extending under cooling plate16, and it cools cooling plate 16. Cooling plate 16 used here is made ofa metallic plate of good thermal conductibility such as aluminum, and ithas a thickness of 2 mm to 15 mm to maintain evenness of temperaturethroughout the cooling surface.

Use of this structure allows a certain degree of flexibility in thearrangement of Peltier device 14.

When cooling plate 16 reaches a freezing temperature, it starts freezingthe supplied water gradually from the bottom side while dispellinggaseous components in the water upward.

Through this duration, the top surface of supplied water remains freefrom freezing since the ambient temperature around ice-making unit 300is kept higher than 0 deg-C. Temperature sensor 35 keeps monitoring atemperature of cooling plate 16, and performs control of the optimumfreezing speed by properly regulating a voltage to Peltier device 14. Inthe case that the freezing speed is faster than the speed of degassing,for instance, the voltage to Peltier device 14 is reduced.

The ice grows upward as the time elapses after the start of ice-making,and a distance of the frozen surface from cooling plate 16 alsoincreases proportionally. In order to maintain the freezing speed on thefrozen surface constant, it is necessary to gradual lower thetemperature of the cooling surface. Such a control of the temperaturecan be achieved by gradually decreasing the voltage to the Peltierdevice with passage of the time.

This ice-making device 67 is disposed inside an ice-making compartmentor a freezer compartment of a refrigerator. Under this circumstance,there is a case that the freezing speed becomes too fast in the initialstage of ice-making because of an effect of the surrounding temperature.In this case, the polarity of voltage applied to Peltier device 14 isreversed to heat the cooling surface for a given time duration from thestart of ice-making in order to optimize the freezing speed.Subsequently, the polarity of voltage is reversed again to start thecooling of the cooling surface until the ice-making is completed.

When temperature sensor 35 detects a temperature rise of cooling plate16 and determines that the water supply is completed, swing drive unit65 starts repeating a normal-to-reverse rotation at a given frequencyand a given amplitude to swing ice-making device 67. As a consequence ofthis operation, the water supplied inside ice-making unit 300 startsflowing smoothly across the ice surface from the upper side to the lowerside by the force of gravity in response to the timing of inclination ofice-making unit 300. The ice surface becomes wet after the water flowstherethrough, thereby leaving an extremely thin layer of the water asobserved microscopically. The swinging motion also stirs the watermoderately, and expedites the degassing. The presence of the extremelythin layer of water substantially reduces the distance for air in thewater to reach the boundary to the atmospheric air, and helps expeditethe degassing.

The water supplied inside ice-making vessel 503 is freely movable acrossan entire width thereof since there is no wall in ice-making unit 300that is generally perpendicular to the swinging direction. A movabledistance of the supplied water in this exemplary embodiment issubstantially large as compared to the conventional ice-making vessel,which is normally divided into a plurality of sections.

This structure improves the effect of degassing so as to produce an iceblock of high clarity inside ice-making unit 300. Or, it can shorten theice-making time if agreeable with equivalent clarity to those generallymade available by the conventional ice-making device.

Temperature sensor 35 detects a temperature drop of cooling plate 16 todetermines the ice-making is completed. The clear ice block made in thismanner is generally plank-shaped. At this completed state, the clear iceblock contains shafts 66 in it, and these shafts 66 are driven byice-cracker drive unit 68 to rotate in a predetermined direction. Eachof shafts 66 is provided with a plurality of ribs or claws protruding inthe radial direction. Rotation of these ribs causes the generallyplank-shaped ice block to crack in areas around the ribs, and breaks theclear ice block into a plurality of pieces. It is desirable that thesecracked ice pieces are properly sized for practical use in the ordinaryhouseholds.

After the ice block is cracked, swing drive unit 65 turns ice-makingdevice 67 into upside down to release and let the clear ice pieces inice-making unit 300 fall downward. Afterwards, swing drive unit 65 turnsin the opposite direction to return ice-making device 67 into the rightposition for waiting the subsequent supply of water.

If shafts 66 and ice-cracker drive unit 68 are not constructed into asingle assembly, both shafts 66 and ice-cracker drive unit 68 need to bemoved from the upper side of ice-making unit 300 toward the ice blockafter the ice block is formed. If this is the case, certain kind ofheating means becomes necessary in order to insert shafts 66 into theice block. Such an ice-making device also requires additional movingmeans for moving shafts 66 and ice-cracker drive unit 68 in the verticaldirection.

It also gives rise to an increase of the ice-making time since the iceblock requires refreezing for cracking after shafts 66 are inserted inthe ice block with the aid of the heating means.

As has been described, the ice-making device of this exemplaryembodiment comprises the cooling plate, the ice-making vessel having anopen top and disposed on the cooling plate, the swing mechanism forswinging the ice-making vessel, and the water supply mechanism forsupplying water to the ice-making vessel, wherein the device is capableof freezing the water while simply making the water flow over an icesurface by the force of gravity, by way of adjusting the amount of watersupply and timing, forming a thin layer of unfrozen water, and swingingthe ice-making vessel.

The ice-making device supplies water in number of divided steps, inwhich an amount of water is increased for the first supply while anamount is fixed for the subsequent supplies, with the total number ofsupplies ranging between 5 and 25 times, and carries out the supplies ofwater in a sequential manner before the water in the ice-making vesselbecomes completely frozen by setting the supply timing appropriately.

The ice-making device can gradually lower the temperature of the bottomsurface of the ice-making vessel, or the surface of the cooling plate,beginning from the start of ice-making, by controlling it with thetemperature detection means mounted to the ice-making unit.

The cooling plate is made of a metallic plate of good thermalconductibility having a thickness ranging between 2 mm and 15 mm tomaintain uniform temperature throughout its surface.

The ice-making device uses a Peltier device for cooling the coolingplate, and thereby it can regulate temperature of the cooling surface tothe optimum temperature.

The method of controlling power supply to the Peltier device includesreversing the polarity of the supply voltage when a predetermined timeis elapsed after the start of the ice-making, to change the cooling andheating of the cooling surface.

The ice-making device further comprises a heating means disposed to theice-making vessel or in the vicinity thereof for controlling thesurrounding temperature of the ice-making vessel in order to prevent thewater on the surface of the ice-making unit from freezing.

Eleventh Exemplary Embodiment

Description is provided of an ice-making device of the eleventhexemplary embodiment with reference to FIG. 23 and FIG. 24.

Like reference numerals are used to designate like components as thoseof the eighth exemplary embodiment, and details of them will be skipped.

Ice-making unit 300 comprises ice-making vessel 503 having an open topand open bottom for temporarily storing water and making a plank-shapedblock of ice, cooling plate 16, and water sealing member 30 disposedbetween ice-making vessel 503 and cooling plate 16. Drive unit 39 isdisposed underneath cooling plate 16. Cooling accelerate member 140having a fin configuration is disposed behind drive unit 39 and undercooling plate 16 in a manner to make close contact to cooling plate 16.Both cooling plate 16 and cooling accelerate member 140 are formed of amaterial of good thermal conductivity such as aluminum. In addition,heater 41 is disposed to cooling plate 16 in a location outside of butclose to ice-making vessel 503, for heating cooling plate 16.

Ice-making vessel 503, cooling plate 16, water sealing member 30, driveunit 39 and cooling accelerate member 140 are assembled in a manner tobe sandwiched from the top and bottom by supporting members 142 and 143.

In this structure, ice-making vessel 503 is pressed in the directions ofcooling plate 16 by supporting members 142 and 143, while also imposinga moderate compression on water sealing member 30.

A plurality of shafts 66 are connected to drive unit 39, and theypenetrate through cooling plate 16 and extend in the direction ofice-making unit 300. Through-holes in cooling plate 16 are provided withwater sealing members 33 for sealing spaces around shafts 66. Inaddition, drive unit 39 is provided with ice detector shaft 144 disposedon the side thereof, and ice detecting lever 145 is mounted to icedetector shaft 144. Drive unit 39 is also provided with driving shaft 54on the front side.

Drive unit 39 includes therein at least one driving component, thoughnot shown in the figures, for driving shafts 66, ice detector shaft 144and driving shaft 54

Cooling plate 16 is provided with temperature detection means such astemperature sensor 35.

Insulating materials 147 and 148 for covering heater 141 and temperaturesensor 35 are placed around ice-making vessel 503.

Ice-making vessel 503, cooling plate 16, water sealing member 30, driveunit 39, cooling accelerate member 140, heater 141, supporting members142 and 143, shafts 66, water sealing members 33, ice detector shaft144, ice detecting lever 145, driving shaft 54, temperature sensor 35and insulating materials 146 and 147 are secured one another to composeice-making device 37 as a whole.

Cooling accelerate member 140 is located in an area confronting a coldair port inside of a refrigerator's ice-making compartment (not shown).

Ice-making device 37 is placed inside the ice-making compartment in amanner that its upper portion is housed in a space of generally adome-shaped concaved portion formed in the top surface of thecompartment. Insulating materials 146 and 147 are closely located to theconcaved portion in the top surface of the compartment to an utmostextent without interfering rotation of ice-making device 37 whileminimizing circulation of the air through ice-making unit 300 and theice-making compartment. The top surface of the ice-making compartment isequipped with heating means inside the concaved portion, though notshown in the figures.

The ice-making device constructed as above operates and functions in amanner which is described hereinafter.

When the ice-making control begins and temperature sensor 35 detects atemperature within a predetermined range, water is supplied by the watersupply means and stored in a space of ice-making unit 300 bounded byice-making vessel 503 and cooling plate 16. Ice-making vessel 503 has anopen bottom from where cooling plate 16 is exposed.

The water stored in ice-making unit 300 does not leak out because ofwater sealing member 30 placed between ice-making vessel 503 and coolingplate 16. Water sealing members 33 disposed around shafts 66 alsoprevent the water from leaking out of ice-making unit 300.

Water sealing members 33 are formed of a rubber-like elastic materialinto an annular shape.

These water sealing members 33 have one or more stages of fin-likeconfiguration formed along their inner perimeters, and their innerdiameters are smaller than the outer diameter of shafts 66. Moreover,the inner perimeters of water sealing members 33 are coated with greaseto further improve the waterproofing property.

When temperature sensor 35 detects a temperature rise of cooling plate16 and determines that the water supply is completed, driving shaft 54starts repeating a normal-to-reverse rotation at a given frequency and agiven amplitude to swing ice-making device 37, and moderately stirs thewater supplied inside ice-making unit 300. In this embodiment, drivingshaft 54 is fixed to the ice-making compartment, so that the rotation ofdriving shaft 54 causes ice-making device 37 itself to make a swingingmotion.

An ambient temperature surrounding ice-making unit 300 is kept higherthan 0 deg-C., since a concaved portion in top surface of the ice-makingcompartment is heated by a heating means, and insulating materials 146and 147 isolate ice-making unit 300 from the inner air of the ice-makingcompartment. Cooling accelerate member 140 is cooled by chilled airdelivered into the ice-making compartment, and cools cooling plate 16.When cooling plate 16 reaches a freezing temperature, it starts freezingthe supplied water gradually from the bottom side while dispellinggaseous components in the water upward. The top surface of the suppliedwater will never freeze before the bottom surface since the ambienttemperature around ice-making unit 300 is kept higher than 0 deg-C.through this duration. Temperature sensor 35 keeps monitoring atemperature of cooling plate 16. The monitored temperature is used forregulating a voltage applied to heater 141 appropriately or switchingthe power supply to heater 141. The optimum freezing speed is controlledin this manner by regulating the temperature of cooling plate 16. Whenthe freezing speed is faster than the degassing speed, for instance, thevoltage applied to heater 141 is increased. This further enhances thedegassing effect of the swinging operation, that is, the effect ofdispelling gaseous components in the water. At this time, unfrozen waterinside ice-making vessel 503 is freely movable across an entire widththereof.

Completion of the ice-making is determined when the temperature detectedby temperature sensor 35 becomes lower than a predetermined temperatureafter an elapse of a predetermined time following the end of watersupply. A generally plank-shaped ice block of comparatively high clarityis produced by this time in ice-making vessel 503.

The swinging operation stops upon completion of the freezing, and icedetector shaft 144 moves ice detecting lever 145 downward into the icestorage box placed inside the ice-making compartment. If the ice storagebox contains ice chips of an amount exceeding a predetermined level, icedetecting lever 145 touches the ice and its turning movement obstructedso as to determine that the box is full with the ice. If the ice storagebox contains ice chips of a lesser amount than the predetermined level,on the other hand, ice detecting lever 145 finds the amount of ice notsufficient.

The ice block is kept as it is in ice-making vessel 503 when the storagebox is full. Ice detecting lever 145 is activated thereafter at regularintervals to monitor the amount of ice chips in ice storage box. Heater141 is energized when the ice becomes deficient, to start heatingcooling plate 16. This heat of cooling plate 16 loosens the ice blockbound to cooling plate 16 inside ice-making vessel 503.

Power supply to heater 141 is terminated when temperature sensor 35detects a temperature above a predetermined value. Driving shaft 54 isdriven to turn ice-making unit 300 upside down, and shafts 66 are thenrotated to crack the ice block into a plurality of chips and to let themfall into the ice storage box. After completion of cracking the iceblock, shafts 66 are returned to their original positions, andice-making unit 300 is returned to the horizontal position by drivingdriving-shaft 54.

The ice-making control returns to the start thereafter.

As described above, an ice-making device equipped with a cooling platehaving a heating capability can be realized with a comparatively simplestructure and at low cost by adopting ice-making device 37 of thisexemplary embodiment.

Since the heater is covered with insulating materials on all surfacesother than the one in contact with the cooling plate, it has a low lossof heat, and is capable of bringing up a temperature of the coolingplate to the predetermined level within a short time by itscomparatively small heating capacity.

In this exemplary embodiment, description provided also included themethod of making sensually excellent block of ice with good clarity foruse in whiskey and water and the like. However, the method describedhere is not meant to exclude other methods of ice-making.

Twelfth Exemplary Embodiment

Description is provided of the twelfth exemplary embodiment withreference to FIG. 25.

Detailed description will be skipped for like components as those of theeleventh exemplary embodiment.

Ice-making unit 300 comprises ice-making vessel 503 having an open topand open bottom for temporarily storing water and making a plank-shapedblock of ice, cooling plate 16, and water sealing member 30 disposedbetween outer flange of ice-making vessel 503 and cooling plate 16.

Drive unit 39 is disposed underneath cooling plate 16.

Cooling accelerate member 140 having a fin configuration is disposedbehind drive unit 39 and under cooling plate 16 in a manner to makeclose contact to cooling plate 16. Both cooling plate 16 and coolingaccelerate member 140 are formed of a material of good thermalconductivity such as aluminum.

In addition, flat-type heater 141A capable of generating substantiallyuniform heat is disposed between cooling plate 16 and drive unit 39 in alocation corresponding to the bottom of ice-making vessel 503, for thepurpose of heating cooling plate 16. The flat-type heater for generatingsubstantially uniform heat may be the one comprised of a metal resistorsandwiched between insulators formed of silicone rubber or the like,another one comprised of a heater made of a conductive resin alsosandwiched between insulators, or the like component. They haverelatively high flexibility in design of configuration.

A plurality of shafts 66 are connected to drive unit 39, and theypenetrate through cooling plate 16 and extend in the direction ofice-making unit 300. Through-holes in cooling plate 16 are provided withwater sealing members 33 for sealing spaces around shafts 66. Flat-typeheater 141A has holes cut open in areas corresponding to shafts 66 forthem to penetrate through.

The ice-making device constructed as above operates and functions in amanner which is described hereinafter.

The water supplied by water supply means is cooled by cooling plate 16inside ice-making vessel 503, and becomes frozen.

When temperature sensor 35 detects completion of the freezing, flat-typeheater 141A is energized to heat cooling plate 16 and loosen the iceblock bound to cooling plate 16. Since flat-type heater 141A generatessubstantially uniform heat and heats the bottom surface of ice-makingvessel 503 generally uniformly, the ice block is not likely to meltunevenly.

Although temperature sensor 35 monitors a temperature of only one spotof cooling plate 16 for determination of terminating the heating, thisuniformity of temperature distribution throughout cooling plate 16 canensure the end of heating at the optimum temperature to loosen the iceblock bound to cooling plate 16 without melting.

As described above, the ice-making device of this twelfth exemplaryembodiment has a flat-type heater placed between the cooling plate andthe drive unit in the location corresponding to the bottom of theice-making vessel for generating substantially uniform heat. This heatercan prevent a partial over-melting of the ice block due to heating ofthe cooling plate. It also helps terminate the heating at the optimumtemperature to loosen the ice block bound to the cooling plate.

In this exemplary embodiment, the flat-type heater is disposed betweenthe cooling plate and the drive unit. However, like advantageous effectcan be achieved by using a conventional heating wire instead of theflat-type heater, with addition of a relatively simple structure, inwhich a groove is formed in at least one of the cooling plate and thedrive unit for installation of the heating wire.

TABLE 1A Embodied Total Vessel Amount of Sample Water Bottom Number ofeach Swing Swing Freezing Number (Depth) Area Feedings Feeding AngleFrequency Time Clarity 1 100 ml 40 mm 20 times 4.5 ml   ±15 deg 5 c/m 80 min D  (20 ml) 2 100 ml 40 mm 20 times 4.5 ml   ±15 deg 5 c/m 120min C  (20 ml) 3 160 ml 60 mm 20 times 7 ml ±15 deg 5 c/m 120 min B  (20ml) 4 160 ml 60 mm 40 times 3.5 ml   ±15 deg 5 c/m 120 min D  (20 ml) 5160 ml 60 mm 10 times 15 ml  ±15 deg 5 c/m 120 min B  (20 ml) 6 160 ml60 mm 1 time — ±15 deg 5 c/m 120 min C  (20 ml) 7 160 ml 60 mm 20 times7 ml ±10 deg 5 c/m 120 min C  (20 ml) 8 160 ml 60 mm 20 times 7 ml  ±5deg 5 c/m 120 min D  (20 ml) 9 160 ml 60 mm 20 times 7 ml ±15 deg 2 c/m120 min D  (20 ml) 10 160 ml 60 mm 20 times 7 ml ±15 deg 15 c/m  120 minD  (20 ml) 11 160 ml 60 mm 20 times 7 ml ±15 deg 5 c/m 240 min A  (20ml) 12 112 ml 60 mm 13 times 7 ml ±15 deg 5 c/m 120 min A  (15 ml) 13112 ml 60 mm 1 time — ±15 deg 5 c/m 120 min B  (15 ml) 14 112 ml 60 mm 1time —  0 deg — 120 min D  (15 ml) 15 112 ml 60 mm 1 time —  0 deg — 240min C  (15 ml) 16 200 ml 60 mm 1 time — ±15 deg 5 c/m 120 min D  (25 ml)17 160 ml 60 mm 20 times 7 ml ±15 deg 10 c/m  120 min C  (20 ml) 18 160ml 60 mm 30 times 4.5 ml   ±15 deg 5 c/m 120 min C  (20 ml)

TABLE 1B Embodied Total Vessel Amount of Sample Water Bottom Number ofeach Swing Swing Freezing Number (Depth) Area Feedings Feeding AngleFrequency Time Clarity 14 112 ml 60 mm 1 time — 0 deg — 120 min D  (15ml) 15 112 ml 60 mm 1 time — 0 deg — 240 min C  (15 ml)

TABLE 1C Embodied Total Vessel Amount of Sample Water Bottom Number ofeach Swing Swing Freezing Number (Depth) Area Feedings Feeding AngleFrequency Time Clarity 13 112 ml 60 mm 1 time 112 ml ±15 deg 5 c/m 120min B  (15 ml) 6 160 ml 60 mm 1 time 160 ml ±15 deg 5 c/m 120 min C  (20ml) 16 200 ml 60 mm 1 time — ±15 deg 5 c/m 120 min D  (25 ml)

TABLE 1D Embodied Total Vessel Amount of Sample Water Bottom Number ofeach Swing Swing Freezing Number (Depth) Area Feedings Feeding AngleFrequency Time Clarity 2 100 ml 40 mm 20 times 4.5 ml ±15 deg 5 c/m 120min C  (20 ml) 3 160 ml 60 mm 20 times   7 ml ±15 deg 5 c/m 120 min B (20 ml)

TABLE 1E Embodied Total Vessel Amount of Sample Water Bottom Number ofeach Swing Swing Freezing Number (Depth) Area Feedings Feeding AngleFrequency Time Clarity 3 160 ml 60 mm 20 times 7 ml ±15 deg 5 c/m 120min B  (20 ml) 7 160 ml 60 mm 20 times 7 ml ±10 deg 5 c/m 120 min C  (20ml) 8 160 ml 60 mm 20 times 7 ml  ±5 deg 5 c/m 120 min D  (20 ml)

TABLE 1F Embodied Total Vessel Amount of Sample Water Bottom Number ofeach Swing Swing Freezing Number (Depth) Area Feedings Feeding AngleFrequency Time Clarity 9 160 ml 60 mm 20 times 7 ml ±15 deg  2 c/m 120min D  (20 ml) 3 160 ml 60 mm 20 times 7 ml ±15 deg  5 c/m 120 min B (20 ml) 17 160 ml 60 mm 20 times 7 ml ±15 deg 10 c/m 120 min C  (20 ml)10 160 ml 60 mm 20 times 7 ml ±15 deg 15 c/m 120 min D  (20 ml)

TABLE 1G Embodied Total Vessel Amount of Sample Water Bottom Number ofeach Swing Swing Freezing Number (Depth) Area Feedings Feeding AngleFrequency Time Clarity 6 160 ml 60 mm 1 time — ±15 deg 5 c/m 120 min C (20 ml) 5 160 ml 60 mm 10 times  15 ml ±15 deg 5 c/m 120 min B  (20 ml)3 160 ml 60 mm 20 times   7 ml ±15 deg 5 c/m 120 min B  (20 ml) 18 160ml 60 mm 30 times 4.5 ml ±15 deg 5 c/m 120 min C  (20 ml) 4 160 ml 60 mm40 times 3.5 ml ±15 deg 5 c/m 120 min D  (20 ml)

INDUSTRIAL APPLICABILITY

The ice-making device of the present invention has an ice-making unitfor making a plank-shaped block of ice, and cracking means for crackingthe plank-shaped ice block into a plurality of chips, thereby providingsharp-cut ice chips rather than round-edge cubes. The device can broadlysatisfy the need of ice chips with varied shapes for ice makers,refrigerators and the like of not only household use but also commercialuse. Usefulness of the ice-making device of this invention isunlimitedly wide because of a high commercial value of the device besidethe attractiveness of the high clarity of ice chips.

1. An ice-making device comprising: an ice-making unit provided with anice-making vessel for making a plank-shaped block of ice; cracking meansfor cracking the plank-shaped block of ice produced in the ice-makingunit into a plurality of irregularly-shaped ice chips within theice-making unit; a drive unit for driving the cracking means; a watersupply unit for supplying water to the ice-making vessel; a turning unitfor turning the ice-making unit upside down; and an ice storage box forstoring the plurality of irregularly-shaped ice chips, wherein thecracking means is disposed to a bottom side of the ice-making vessel,and the turning unit turns the ice-making vessel and the cracking meansupside down upon completion of the ice making to allow the ice chips inthe ice-making vessel to fall into the ice storage box.
 2. Theice-making device according to claim 1, wherein the cracking meanscracks the plank-shaped block of ice by providing a stress internallythereon.
 3. The ice-making device according to claim 1 furthercomprising a drive unit for driving the cracking means, and the crackingmeans comprises a shaft driven and rotated by the drive unit.
 4. Theice-making device according to claim 3, wherein the shaft is providedwith a plurality of ribs extending generally radially from a rotatingaxis of the shaft.
 5. The ice-making device according to claim 4,wherein the ribs are formed in a manner that a protruding length in theradial direction is longer at the bottom side is than a length at theupper side.
 6. The ice-making device according to claim 3, wherein theshaft is inserted in advance in the ice-making vessel before the waterinside the ice-making vessel freezes.
 7. The ice-making device accordingto claim 6, wherein a height of the shaft in horizontal plane is tallerthan a height of the ice made in the ice-making vessel.
 8. Theice-making device according to claim 6, wherein a height of the shaft inhorizontal plane is shorter than a height of the ice made in theice-making vessel.
 9. The ice-making device according to claim 3,wherein the shaft is inserted through the bottom of the ice-makingvessel.
 10. The ice-making device according to claim 9, wherein theshaft is placed over outer periphery of a cylindrical post mounted tothe bottom of the ice-making vessel, and connected with the drive unitthrough the interior of the cylindrical post.
 11. The ice-making deviceaccording to claim 3, wherein the cracking means is provided with aplurality of shafts, and the drive unit rotates the plurality of shaftssimultaneously.
 12. The ice-making device according to claim 11, whereineach of the plurality of shafts has a rib formed substantially inalignment with another along a line connecting a rotating axes of theadjoining shafts, and the plurality of shafts are driven in the samerotating direction.
 13. The ice-making device according to claim 11,wherein each of the plurality of shafts has a rib formed substantiallyin alignment with another along a line connecting a rotating axes of theadjoining shafts, and the plurality of shafts are driven in differentrotating directions with respect to one another.
 14. The ice-makingdevice according to claim 3, wherein the shaft is formed of a metal. 15.The ice-making device according to claim 3, wherein the shaft is formedof a polymeric resin.
 16. The ice-making device according to claim 1,wherein the ice-making unit is fixed to the cracking means, and theice-making unit and the cracking means swing around a horizontal turningshaft when ice is being made.
 17. The ice-making device according toclaim 1, wherein the ice-making vessel has sidewalls sloped in adirection to make a top plane larger in area than an area of a bottomplane.
 18. The ice-making device according to claim 1 further comprisinga turning unit for turning the ice-making unit upside down, wherein thecracking means is driven to crack the plank-shaped block of ice into theplurality of irregularly-shaped ice chips after the ice-making iscompleted and the ice-making unit is turned upside down.
 19. Theice-making device according to claim 18, wherein the cracking means isdriven further for a predetermined time duration while the ice-makingunit is in the upside-down position.
 20. The ice-making device accordingto claim 18, wherein the cracking means is for driving a shaft to rotatein one direction when cracking the block of ice, and the cracking meansdrive the shaft in the same direction as that for cracking the ice for apredetermined time duration after the cracking but before supplyingwater to the ice-making unit.
 21. The ice-making device according toclaim 18, wherein the ice-making unit is turned upside down and thecracking means is driven after the ice-making is completed and thebottom surface of the ice-making vessel is heated.
 22. The ice-makingdevice according to claim 18, wherein the bottom surface of theice-making vessel is cooled to a predetermined temperature followingcompletion of releasing the ice chips from the ice-making vessel butbefore starting the supply of water.
 23. The ice-making device accordingto claim 18, wherein an ice storage box is disposed under the ice-makingunit for storing ice chips, and further wherein the ice-making unit isturned upside down and the shaft is driven, after the ice-making iscompleted and an amount of the ice chips in the ice storage box isdetermined and found less than a predetermined level.
 24. The ice-makingdevice according to claim 23, wherein a temperature of the ice-makingvessel is controlled to be 0 deg-C. or below when an amount of the icechips in the ice storage box is found to satisfy the predeterminedlevel.
 25. The ice-making device according to claim 1 further comprisinga turning unit for turning the ice-making unit upside down, wherein theice-making unit is turned upside down after the ice-making is completedand the cracking means is driven to crack the plank-shaped block of iceinto the plurality of irregularly-shaped ice chips.
 26. The ice-makingdevice according to claim 1 further comprising a turning unit forturning the ice-making unit upside down, wherein the cracking means isdriven to crack the plank-shaped block of ice into the plurality ofirregularly-shaped ice chips when the ice-making is completed, whileturning the ice-making unit upside down.
 27. The ice-making deviceaccording to claim 1, wherein the plank-shaped block of ice made by theice-making unit has a high clarity.
 28. The ice-making device accordingto claim 27 further comprising a swinging mechanism for swinging theice-making vessel during ice-making, wherein the swinging mechanismcauses the water to flow while being frozen into the plank-shaped blockof ice.
 29. The ice-making device according to claim 28, wherein theswinging is carried out at a frequency of 3 to 10 cycles per minute fromthe start to the completion of ice-making.
 30. The ice-making deviceaccording to claim 28, wherein an angle of the swinging is in a range of±10 degrees and ±20 degrees.
 31. The ice-making device according toclaim 28, wherein the swinging is paused for a duration of 3 to 7seconds at a point of the largest swinging angle.
 32. The ice-makingdevice according to claim 27, wherein the water supply unit supplies thewater to the ice-making vessel intermittently in a plural number oftimes using intermittent water supply means.
 33. The ice-making deviceaccording to claim 27 further comprising heating means under theice-making vessel, wherein the heating means heats a bottom surface ofthe ice-making vessel to a predetermined temperature followingcompletion of releasing the ice chips but before starting the supply ofwater.
 34. The ice-making device according to claim 27, wherein theice-making vessel has sidewalls sloped in a direction to make a topplane larger in area than an area of a bottom plane, and the slopedsurfaces have any angle between 10 and 39 degrees.
 35. The ice-makingdevice according to claim 34, wherein the sidewalls of the ice-makingvessel are partly bent inward.
 36. The ice-making device according toclaim 1, wherein a temperature of a bottom surface of the ice-makingvessel is regulated using temperature detection means mounted to theice-making unit in a manner to gradually decrease from the start ofice-making.
 37. The ice-making device according to claim 1 furtherhaving a cooling plate formed of a metal of good thermal conductivityfor cooling the ice-making vessel.
 38. The ice-making device accordingto claim 37, wherein a surface temperature of the cooling plate isregulated using temperature detection means mounted to the ice-makingunit in a manner to decrease the temperature of the cooling plategradually from the start of ice-making.
 39. The ice-making deviceaccording to claim 38 further having a control unit for power supply tothe Peltier device, wherein a polarity of voltage applied to the Peltierdevice is reversed to switch between cooling and heating when apredetermined time has elapsed after the start of ice-making.
 40. Theice-making device according to claim 37, wherein the cooling plate iscooled by using a Peltier device.
 41. The ice-making device according toclaim 37, wherein the cooling plate is provided with a heater forcontrolling an ambient temperature of the ice-making vessel.
 42. Theice-making device according to claim 1 further provided with heatingmeans for controlling an ambient temperature of the ice-making vessel.43. The ice-making device according to claim 1, wherein the ice-makingunit is provided with a heater for heating.
 44. The ice-making deviceaccording to claim 43, wherein the heater comprises a flat-type heaterfor generating substantially uniform heat throughout a surface thereof.